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Electronics => Renewable Energy => Topic started by: fourtytwo42 on January 11, 2018, 08:32:20 pm

Title: UK solar doldrums
Post by: fourtytwo42 on January 11, 2018, 08:32:20 pm
We seem to be surrounded in clag, the utilities must be rubbing there hands with glee!!

My daily output here in Norfolk has been zero for several days and down to 0.2Kw/h average per Kw installed this week, anybody doing any better ?
Title: Re: UK solar doldrums
Post by: DenzilPenberthy on January 11, 2018, 10:20:38 pm
It's sunny clear blue sky here in Bristol..
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 12, 2018, 03:17:04 am
It's sunny clear blue sky here in Bristol..
Dang just have to move house then :)
Title: Re: UK solar doldrums
Post by: tggzzz on January 12, 2018, 03:22:00 am
According to http://www.gridwatch.templar.co.uk/ (http://www.gridwatch.templar.co.uk/) UK solar output peaked at ~2GW today. vs 4GW last Sunday.
Title: Re: UK solar doldrums
Post by: stj on January 12, 2018, 04:14:44 am
i dont think the suppliers are too happy actually.
there is a gas shortage right now because a transfer center in Europe went up in flames over the new year.
the u.k. is now breaking it's own sanctions buying emergency gas shipments from Russia - and i bet they are not selling it cheap!!
Title: Re: UK solar doldrums
Post by: metrologist on January 12, 2018, 04:39:47 am
why not? supply is tight so double the margins. end consumers will pay for it...
Title: Re: UK solar doldrums
Post by: tggzzz on January 12, 2018, 05:42:28 am
why not? supply is tight so double the margins. end consumers will pay for it...

Many individuals are on fixed price contracts, and they change supplier regularly.

I would expect that businesses have similar arrangements.
Title: Re: UK solar doldrums
Post by: stj on January 12, 2018, 05:49:48 am
blame the government.
they are to blame for alienating the region's biggest fuel suppliers.

we could have cheap russian gas and cheap iranian oil,
but oh-no - that would upset the stateless shadow-scumbags  working with government to carry out petty revenge against country's that are still independent from central banking!
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 12, 2018, 05:57:03 am
According to http://www.gridwatch.templar.co.uk/ (http://www.gridwatch.templar.co.uk/) UK solar output peaked at ~2GW today. vs 4GW last Sunday.
It's a long time since I looked there and I don't think they used to have solar seperated out, anyway I note with interest whilst solar has dipped badly in the winter Bio is takeing off and I spent a few days this week making compost from all the annual hedge cuttings etc, now theres an idea  :-+ principle must be similar to brewing beer/wine right ?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 12, 2018, 06:01:59 am
I didnt think we had a gas pipeline connection to europe BUT we have shutdown one of the feeds from the north sea due to a fracture that will take a good while to repair. Interesting that story about the russian LPG ship unloading at the thames estury, it was claimed to be a transfer shipment only and anyway I thought our bulk LPG import was tother side of country (all locations left vague deliberatly).
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 06:37:26 am
blame the government.
they are to blame for alienating the region's biggest fuel suppliers.

we could have cheap russian gas and cheap iranian oil,
but oh-no - that would upset the stateless shadow-scumbags  working with government to carry out petty revenge against country's that are still independent from central banking!


Let's keep the politics out please.
Title: Re: UK solar doldrums
Post by: metrologist on January 12, 2018, 06:59:26 am
why not? supply is tight so double the margins. end consumers will pay for it...

Many individuals are on fixed price contracts, and they change supplier regularly.

I would expect that businesses have similar arrangements.

I'm not familiar with those kinds of contracts.
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 07:31:15 am
in the UK you sign up for an energy supply contract that lasts for a certain time. The price is fixed for the durationso if there is a massive hike in price you don't pay it until you need to renew. On the one hand you get a better deal, on the other you are locked to a supplier for at least 1 year. suppliers often offer a discount on your first year to get you hooked and hope you don't move on after the first contract is up.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 12, 2018, 07:51:36 am
I am suprised that nobody so far has added there own figures so I added a survey (wow that was easy) as a teaser, maybe I am verging on being an ECO nut hahaha please join in the fun :)
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 08:41:50 am
I'm kicking out about 200W each day but my panels are a bit shaded at the moment being in the garden and with part of a tree in front of them on the ground. The panels are 1.5KW maximum output is usually 1.1KW in the height of summer.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 12, 2018, 08:53:50 am
I'm kicking out about 200W each day but my panels are a bit shaded at the moment being in the garden and with part of a tree in front of them on the ground. The panels are 1.5KW maximum output is usually 1.1KW in the height of summer.
You must be somewhere sunny like Bristol :) I am getting only 30W peak and like 9W average atm from a 1.1Kw array but hey it's really awfull weather here atm. BTW my energy logger is a bit primative (as it was written by me) and has a threshold of 100W/h before it logs anything, hence reporting zero the last few days!
Is that 200W instantanios or watt/hours or watt (pun) ?
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 07:00:41 pm
that's 200 watts for the day I think I have seen it peak at 150W instant. Oh you have a threshold of 100W? you didn't design the powervault did you ? ;)
Title: Re: UK solar doldrums
Post by: tggzzz on January 12, 2018, 08:45:23 pm
that's 200 watts for the day I think I have seen it peak at 150W instant. Oh you have a threshold of 100W? you didn't design the powervault did you ? ;)

What do you mean "200W for the day"? If it is for a day then the units should be kWh or Joules (i.e. energy not power).
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 08:52:37 pm
What do you think ? what would my inverter say? how would I value it and how do the rest of us value it? we are talking standard energy delivery not physics, what unit does the world use to measure generation and consumption of power????
Title: Re: UK solar doldrums
Post by: tggzzz on January 12, 2018, 09:12:33 pm
What do you think ? what would my inverter say? how would I value it and how do the rest of us value it? we are talking standard energy delivery not physics, what unit does the world use to measure generation and consumption of power????

This is O-level physics; look at any electricity meter: kWh.

Watts are by definition Joules per second, i.e. energy/time. Hence kWh is energy/time*time => energy.

In the context of power systems, energy/kWh indicates how much useful work you can do whereas power/kW indicates how fast you can do it.

If you like analogies, in the context of cars kW indicates how fast you can go, kWh indicates how far you can go.
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 09:16:22 pm
Of course it is KWh, in this context it should be unmistakably KWh!
Title: Re: UK solar doldrums
Post by: tggzzz on January 12, 2018, 09:21:26 pm
What do you think ? what would my inverter say? how would I value it and how do the rest of us value it? we are talking standard energy delivery not physics, what unit does the world use to measure generation and consumption of power????

This is O-level physics; look at any electricity meter: kWh.

Watts are by definition Joules per second, i.e. energy/time. Hence kWh is energy/time*time => energy.

In the context of power systems, energy/kWh indicates how much useful work you can do whereas power/kW indicates how fast you can do it.

If you like analogies, in the context of cars kW indicates how fast you can go, kWh indicates how far you can go.
Of course it is KWh, in this context it should be unmistakably KWh!

Greenwashers and publicity machines frequently get this wrong through ignorance and/or deceit. It becomes impossible to determine what their statements mean.
Title: Re: UK solar doldrums
Post by: Simon on January 12, 2018, 09:23:47 pm
Yes I'm sure they do but we are talking about a standardised thing using standard off the shelf kit, I'd be very surprised if anyone inverter stated anything different for "KW" than KWh, most people don't even understand the concept of instantaneous energy at which point you end up talking joules and coulombs just for it to make sense in your head.
Title: Re: UK solar doldrums
Post by: metrologist on January 13, 2018, 02:52:11 am
So, you meant 200 kWh / day from your 1.5 kW panel array?  :-//

I got 70Wh out of my 100W panel yesterday, but there is no load other than an old FLA...
Title: Re: UK solar doldrums
Post by: ahbushnell on January 13, 2018, 03:03:31 am
What do you think ? what would my inverter say? how would I value it and how do the rest of us value it? we are talking standard energy delivery not physics, what unit does the world use to measure generation and consumption of power????
I don't understand your statement?
Power=watts or kW
Energy=joules or kW*hr or MW*hr ....
Title: Re: UK solar doldrums
Post by: tggzzz on January 13, 2018, 03:47:41 am
Yes I'm sure they do but we are talking about a standardised thing using standard off the shelf kit, I'd be very surprised if anyone inverter stated anything different for "KW" than KWh, most people don't even understand the concept of instantaneous energy at which point you end up talking joules and coulombs just for it to make sense in your head.

Any inverter that has a spec in kWh is simply and grossly wrong.

"Instantaneous energy" has a simpler name: energy.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 03:58:14 am
well no inverters tend to tell you how much KWh the power they are delivering is equivalent to. Obviously this figure fluctuates, no inverter tells you in Ws or any other arbitrary unit. Watts by its very definition is a time related definition so we do standardize on KWh or the amount of KWh the current level of power is equivalent to if sustained for an hour. If you want to talk instantaneous power you either still have to narrow it down to a time frame however small and ridiculous or move to a unit that describes a quantity of energy in joules. The same goes for amps, what is an amp? it's 1 coulomb per second or 3600 coulombs per hour, you can't refer to amps without inferring a time frame.
Title: Re: UK solar doldrums
Post by: metrologist on January 13, 2018, 04:13:31 am
I installed a DC meter that displays volts, amps, W, and Whr. I think I can change it to display Ah as well. Since my panel is 100W, I like the W reading also indicates the % output from the panel.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 04:18:42 am
but your Wh presumably is simply an accumulation of instantaneous measurements that if maintained for an hour will give you the same in W as in Wh, as I have just explained watts is a time based definition so when you say "instant watts" what you really mean is a level of power that if maintained for an hour will give this W as Wh. as a solar panel output varies you can't measure the power delivered now in equivalent Wh and assume it will last for an hour. so multiple instantaneous levels are given that are integrated to give your actual Wh.
Title: Re: UK solar doldrums
Post by: metrologist on January 13, 2018, 04:41:33 am
It did not seem the math was that complex. The W display is the instantaneous output. The Wh accumulates over time, and I suspect the algorithm is probably very linear. I'm sure it just takes a sample of VxA at periods and adds the normalized value.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 04:45:31 am
Yes you are measuring the volts and amps now and assume they remain the same until the next sample, divide the results by the amount of samples per hour and add them together. For example if you take a sample every second you calculate the current watts (Wh) and divide the result by 3600 and then keep doing that every second and add the results together. After 1 hour you will have the average Wh delivered.
Title: Re: UK solar doldrums
Post by: stj on January 13, 2018, 05:04:08 am
i would be very suspicious of meters that show Ah or Wh,
they probably take one sample and do some math on it.
using the assumption that supply/usage is stable.
highly unlikely that most meters actually use bulk sampling unless they activly advertise a logging or graphing function.
Title: Re: UK solar doldrums
Post by: tggzzz on January 13, 2018, 05:46:58 am
well no inverters tend to tell you how much KWh the power they are delivering is equivalent to.

Of course they don't! That would be as non-sensical as equating "miles" with "miles per hour".

It would be entirely reasonable for them to state "you are currently generating x kW, and over the last day you have delivered y kWh", or "you are currently going at x mph and over the past day you have travelled y miles".
Title: Re: UK solar doldrums
Post by: tggzzz on January 13, 2018, 05:55:58 am
Watts by its very definition is a time related definition

Power is not a "time related" concept per se.

Quote
If you want to talk instantaneous power you either still have to narrow it down to a time frame however small and ridiculous or move to a unit that describes a quantity of energy in joules.

Er no. That's what calculus is all about.

Energy is the integral of power over time.

Quote
you can't refer to amps without inferring a time frame.

Er no. I have a current of 5 amps flowing. There is no need for any timeframe.

If, OTOH, you want to discuss how many coulombs have passed when a 5 amp current is flowing, then you have to state a time interval - since charge is the integral of current over time.
Title: Re: UK solar doldrums
Post by: Avacee on January 13, 2018, 06:36:59 am
As an example of how overcast its been here in North-West England; pretty much all the solar-powered road signs weren't working when I was driving this lunchtime/afternoon.
E.g. the happy/sad faces you get as speed reminders ..

Does anyone know how much battery capacity those types of signs typically have?

Title: Re: UK solar doldrums
Post by: metrologist on January 13, 2018, 07:02:37 am
i would be very suspicious of meters that show Ah or Wh,
they probably take one sample and do some math on it.
using the assumption that supply/usage is stable.
highly unlikely that most meters actually use bulk sampling unless they activly advertise a logging or graphing function.

probably. it's on the order of one of those USB power monitor things, which I have a couple. They show me volts, amps, amp hours, and watt hours. looks like they update about once per second, so that is probably a reasonable enough calculation.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 13, 2018, 07:06:49 am
that's 200 watts for the day I think I have seen it peak at 150W instant. Oh you have a threshold of 100W? you didn't design the powervault did you ? ;)
Umm no I didnt design the powervault does it have a threshold ?
Well the reason I have one is I am in it for the long term so every hour write the accumalated watt/hours to an EEPROM but being mean squash it into one byte, so thats one place a comprimise is made and then the other is the display, I only use a 2x40 char LCD with lots of stuff on it so various energy readings get displayed as 10ths of Kwh. Primative I admit but then I dont want a PC running 24/7 and economics preclude something like a raspi for me anyway :) I should explain I personally don't rely upon a GTI display as the GTI only get's fired up when the water tank is >64degC and that is where most of the power is used, water heating :) Actually saves a significent amount of Oil especially in summer :)
I loved the to and fro here about instantanious power vs energy over time, can be confusing at times (inadvertant pun alert)!
Hey I got 700Wh (0.7Kwh) today, the clag is lifting a little, maybe I dont have to move to Bristol :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 13, 2018, 07:14:56 am
If, OTOH, you want to discuss how many coulombs have passed
Thats naughty introducing yet another confusing measure  :-// :)
Ohh I apologise I see Simon started it  :-\
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 07:22:12 am
well no inverters tend to tell you how much KWh the power they are delivering is equivalent to.

Of course they don't! That would be as non-sensical as equating "miles" with "miles per hour".

It would be entirely reasonable for them to state "you are currently generating x kW, and over the last day you have delivered y kWh", or "you are currently going at x mph and over the past day you have travelled y miles".

erm yes it is exactly like that, miles per hour describes the distance you travel in an hour, again time related, just because you are doing 60mph now does not mean that you will travel 60 miles in one hour unless you keep at that speed, your speed may vary, if you look once at your speedo and it says 60 and you never look at it again and assume you will travel 60 miles in one hour you will find yourself quite wrong.

you cannot say that you will produce 200Wh just because your power meter says that you are making the equivalent of 200Wh in that instant no more than you can say that you will travel 60 miles just because now you are traveling at a speed that will take you 60 miles in one hour. if your power output varies and say for 1/2 hour you produce nothing and for 1/2 hour you produce 200W you will produce 100Wh over the hour but not the 200Wh that was shown as the instant equivalent when you happened to look at the meter.

even if they say you are generating x KW it is still a figure of equivalence to x KWh if you sustain that KWh over the period of one hour. I'll check what mine says tomorrow.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 07:25:29 am
If, OTOH, you want to discuss how many coulombs have passed
Thats naughty introducing yet another confusing measure  :-// :)
Ohh I apologise I see Simon started it  :-\

W = J*s,
A = C*s

There is always a reference to time, if you want to take time out of it you will talk in units of C not A and units of J not W, any measurement of W or A is an assumption over time and can be only taken as an equivalent or verified after 1 hour if it is to be Ah or Wh, we could equally use minutes or seconds but for general transmission, storage and generation we use the hour as the unit of time
Title: Re: UK solar doldrums
Post by: metrologist on January 13, 2018, 07:33:43 am
Well, yeah, but I am using a 60 watt light bulb, and it was drawing 5 amps.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 07:37:43 am
yes and if you run your 60 "watt" lightbulb for 1 hour it will use 60Wh, you could say it uses 1Wm (W') or 1/60W" ;)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 13, 2018, 07:43:11 am
any measurement of W or A is an assumption over time and can be only taken as an equivalent or verified after 1 hour if it is to be Ah or Wh, we could equally use minutes or seconds but for general transmission, storage and generation we use the hour as the unit of time
I think the word equivalent is important and it need not be verified, for example if 300W is measured for 30 minutes it is correct to quantify it as 600Wh because that is the equivalent hourly energy production. I have some Kwh displays that update every minute (for example how much energy have I consumed today), its just a ratiometric progression.

BTW I see we have added miles into the mix now :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 13, 2018, 07:45:03 am
Well, yeah, but I am using a 60 watt light bulb, and it was drawing 5 amps.
Then it's a 12V bulb right and every hour it will use 60Wh of energy :)
Title: Re: UK solar doldrums
Post by: GeorgeOfTheJungle on January 13, 2018, 07:53:01 am
if 300W is measured for 30 minutes it is correct to quantify it as 600Wh because that is the equivalent hourly energy production.

300W * 1/2h = 150 Wh
Title: Re: UK solar doldrums
Post by: GeorgeOfTheJungle on January 13, 2018, 08:08:59 am
yes and if you run your 60 "watt" lightbulb for 1 hour it will use 60Wh, you could say it uses 1Wm (W') or 1/60W" ;)

Watt the... ?? No.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:14:01 am
yes and if you run your 60 "watt" lightbulb for 1 hour it will use 60Wh, you could say it uses 1Wm (W') or 1/60W" ;)

Watt the... ?? No.

Why ? when we say 60W we are implying 60 watts over 1 hour period or 60Wh or 216'00 Joules in one hour.

Where people can be justified for being pedantic is in defining battery storage where Wh is really a good precisation to make, but in ongoing energy use/generation/flow watts is generally meant in one hour period unless otherwise specified.
Title: Re: UK solar doldrums
Post by: ahbushnell on January 13, 2018, 08:34:54 am
If, OTOH, you want to discuss how many coulombs have passed
Thats naughty introducing yet another confusing measure  :-// :)
Ohh I apologise I see Simon started it  :-\

W = J*s,
A = C*s

There is always a reference to time, if you want to take time out of it you will talk in units of C not A and units of J not W, any measurement of W or A is an assumption over time and can be only taken as an equivalent or verified after 1 hour if it is to be Ah or Wh, we could equally use minutes or seconds but for general transmission, storage and generation we use the hour as the unit of time

watts are joules per second not times seconds.  So
W=Joule/second
Amps are coulombs per second
A=coul/second.




Title: Re: UK solar doldrums
Post by: GeorgeOfTheJungle on January 13, 2018, 08:36:21 am
yes and if you run your 60 "watt" lightbulb for 1 hour it will use 60Wh, you could say it uses 1Wm (W') or 1/60W" ;)

Watt the... ?? No.

Why ? when we say 60W we are implying 60 watts over 1 hour period or 60Wh or 216'00 Joules in one hour.

Where people can be justified for being pedantic is in defining battery storage where Wh is really a good precisation to make, but in ongoing energy use/generation/flow watts is generally meant in one hour period unless otherwise specified.

No, "watts is generally meant in one hour period" is wrong. Look, the analogy is as tggzzz has told you before, above, this:

power (Watts) = speed (kilometers/hour)
energy (joules) = distance (kilometers)

So if you travel at a speed of 100 km/h for half an hour you have moved 100 km/h * 1/2 h = 50km

In the same vein if you consume energy at a "speed" (power) of 100W for half an hour you have consumed 100 watts * 1/2 h = 50 Wh

Why would you say that 100 km/h "is generally meant in one hour period"? It makes no sense.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:37:03 am
erm yes sorry

W = J/s
A = C/s
Title: Re: UK solar doldrums
Post by: ahbushnell on January 13, 2018, 08:38:44 am
any measurement of W or A is an assumption over time and can be only taken as an equivalent or verified after 1 hour if it is to be Ah or Wh, we could equally use minutes or seconds but for general transmission, storage and generation we use the hour as the unit of time
I think the word equivalent is important and it need not be verified, for example if 300W is measured for 30 minutes it is correct to quantify it as 600Wh because that is the equivalent hourly energy production. I have some Kwh displays that update every minute (for example how much energy have I consumed today), its just a ratiometric progression.

BTW I see we have added miles into the mix now :)

300 watts for 30 minutes is 300 watt* .5 hours =150 watt-hr.

Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:39:58 am
both speed and watts are time related, you have to set a standard unit. 1W = 1J/s but we never intend a watt as the energy (Joules) used in a second but in one hour and probably hence the more accurate but not always used Wh, we would equally say 3600 J/h
Title: Re: UK solar doldrums
Post by: GeorgeOfTheJungle on January 13, 2018, 08:48:37 am
both speed and watts are time related, you have to set a standard unit. 1W = 1J/s but we never inten a watt as the energy (Joules) used in a second but in one hour and probably hence the more accurate but not always used Wh, we would equally say 3600 J/h

Because Wh is not the same as W/h, 1Wh is not 3600 J/h, it is 3600 J, or, if you prefer, 1Wh = 1W * 1h = 1J/s * 3600s = 3600J.

But you're trolling me, no?
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:56:03 am
both speed and watts are time related, you have to set a standard unit. 1W = 1J/s but we never inten a watt as the energy (Joules) used in a second but in one hour and probably hence the more accurate but not always used Wh, we would equally say 3600 J/h

Because Wh is not the same as W/h, 1Wh is not 3600 J/h, it is 3600 J, or, if you prefer, 1Wh = 1W * 1h = 1J/s * 3600s = 3600J.

But you're trolling me, right?

Erm why would I be trollin you?

1W = 1J/s, there are 3600s in 1h, so if you are using 1W for 1h you need to use 3600W as in 3600 J/s, but we usually refer to watts as over an hour period so what might technically be referred to as 1W is actually 1Wh

if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.

Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:57:28 am
what is the difference between Wh and W/h then ?
Title: Re: UK solar doldrums
Post by: coppice on January 13, 2018, 09:41:47 am
what is the difference between Wh and W/h then ?
Wh is a measure of energy - i.e. the first integral of power over time.
W/h is a rate of change of power - i.e. the first differential of power with respect to time. E.g. if a load is increasing by 10W every hour it would be increasing at a rate of 10W/h.
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 09:49:14 am
but I was previously corrected and told that 1W = 1J/s which is intended as joules per second not changing by a rate of 1J every second.
Title: Re: UK solar doldrums
Post by: coppice on January 13, 2018, 09:55:13 am
but I was previously corrected and told that 1W = 1J/s which is intended as joules per second not changing by a rate of 1J every second.
A steady sustained load power of 1W means the consumed energy is increasing by 1 Joule every second
Conversely a steady sustained generated power of 1W means the produced energy is increasing by 1 Joule every second
Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 09:58:26 am
but no one has talked about changing power levels simply constant power use to use x amount per second is usually referred to as W/s same as m/s is speed not changing speed.
Title: Re: UK solar doldrums
Post by: coppice on January 13, 2018, 10:04:38 am
but no one has talked about changing power levels simply constant power use to use x amount per second is usually referred to as W/s same as m/s is speed not changing speed.
m/s is a rate of change of position = distance/time = speed.
W/s is a rate of change of power.

You were the one to introduce rates of change of power, by using the wrong units.
Title: Re: UK solar doldrums
Post by: tggzzz on January 13, 2018, 10:12:05 am
It might help Simon to look at https://cleantechnica.com/2015/02/02/power-vs-energy-explanation/
Title: Re: UK solar doldrums
Post by: tggzzz on January 13, 2018, 10:31:10 am
both speed and watts are time related, you have to set a standard unit. 1W = 1J/s but we never intend a watt as the energy (Joules) used in a second but in one hour and probably hence the more accurate but not always used Wh, we would equally say 3600 J/h

Why are you concentrating on "standard" time units? Power is not the energy transferred in unit time; power is the rate of transfer of energy.

Consider that if you have a resistor that is perfectly thermally insulated, then any of the following will increase its temperature by the same amount:
In all cases the same energy is dumped into the resistor.
Title: Re: UK solar doldrums
Post by: lewis on January 13, 2018, 10:52:13 am
1W = 1J/s, there are 3600s in 1h, so if you are using 1W for 1h you need to use 3600W as in 3600 J/s,

NO! One watt is one watt whether you're using it for an hour or a century. Power is not a time-dependent quantity.

One watt for one hour (1Wh) is 3600 joules. Not 3600 J/s.

but we usually refer to watts as over an hour period so what might technically be referred to as 1W is actually 1Wh

if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.

NO NO NO! We do NOT refer to watts as over an hour period. A 60W lightbulb uses 60 watts even if I switch it on for half a second.

1W is NOT 1Wh. They are completely different units. Watt = power. Wh = energy.

1Wh does NOT equal 3600W. 1Wh = 3600J.

Title: Re: UK solar doldrums
Post by: ahbushnell on January 13, 2018, 01:31:54 pm
1W = 1J/s, there are 3600s in 1h, so if you are using 1W for 1h you need to use 3600W as in 3600 J/s,

NO! One watt is one watt whether you're using it for an hour or a century. Power is not a time-dependent quantity.

One watt for one hour (1Wh) is 3600 joules. Not 3600 J/s.

but we usually refer to watts as over an hour period so what might technically be referred to as 1W is actually 1Wh

if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.

NO NO NO! We do NOT refer to watts as over an hour period. A 60W lightbulb uses 60 watts even if I switch it on for half a second.

1W is NOT 1Wh. They are completely different units. Watt = power. Wh = energy.

1Wh does NOT equal 3600W. 1Wh = 3600J.
I suggest looking at a Physics book.

Title: Re: UK solar doldrums
Post by: Simon on January 13, 2018, 08:06:51 pm
1W = 1J/s, there are 3600s in 1h, so if you are using 1W for 1h you need to use 3600W as in 3600 J/s,

NO! One watt is one watt whether you're using it for an hour or a century. Power is not a time-dependent quantity.

One watt for one hour (1Wh) is 3600 joules. Not 3600 J/s.

but we usually refer to watts as over an hour period so what might technically be referred to as 1W is actually 1Wh

if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.

NO NO NO! We do NOT refer to watts as over an hour period. A 60W lightbulb uses 60 watts even if I switch it on for half a second.

1W is NOT 1Wh. They are completely different units. Watt = power. Wh = energy.

1Wh does NOT equal 3600W. 1Wh = 3600J.



Yes I know that 1Wh is not 3600W I was just trying to emphasis the confusion that can arise. but if 1W = 1J used in one second then the definition of a watt is tied to seconds. So yes 1Wh is 3600 joules because to use 1W for one hour you are burning 1J every second and there are 3600 seconds in one hour so you need a joule for each of them to sustain 1W for 1h and as we measure everything in hours you get 1Wh. If you were to say that this thing uses 1W anyone would assume you are saying it is a 1Wh device and yes in an instant, or second it will have 1W going into it.

We would do just as well to rate storage systems in joules and state how many joules can be put out in a second, minute or hour. If in seconds then it ties directly with the definition of a W so you just say I am using xW as 1 second is small enough to consider instantaneous but as we meter everything in hours we end up saying Wh
Title: Re: UK solar doldrums
Post by: donotdespisethesnake on January 13, 2018, 11:29:01 pm
Good grief, I thought this was supposed to be a technical forum  :palm:

Next time I get pulled over, I will claim to be driving at "22 meters"  :-DD
Title: Re: UK solar doldrums
Post by: tggzzz on January 14, 2018, 12:52:23 am
Good grief, I thought this was supposed to be a technical forum  :palm:

Next time I get pulled over, I will claim to be driving at "22 meters"  :-DD

Alternatively, when somebody asks "how far away is London", you could answer 66mph.
Title: Re: UK solar doldrums
Post by: tggzzz on January 14, 2018, 12:57:02 am
... but if 1W = 1J used in one second then the definition of a watt is tied to seconds. ...

Let's consider a different phenomenon - heartbeats.

What is your heart rate, expressed in beats per minute, bpm? You can add any caveats you feel helpful or appropriate; the answer cannot be exact.

I'll give you my answer later, but I'm curious about your answer or answers.
Title: Re: UK solar doldrums
Post by: lewis on January 14, 2018, 03:23:08 am
I suggest looking at a Physics book.

Not sure what you mean, did I get something wrong?
Title: Re: UK solar doldrums
Post by: ahbushnell on January 14, 2018, 03:38:39 am
I suggest looking at a Physics book.

Not sure what you mean, did I get something wrong?
Yes
Title: Re: UK solar doldrums
Post by: lewis on January 14, 2018, 03:45:53 am
Yes

Care to elaborate?
Title: Re: UK solar doldrums
Post by: ahbushnell on January 14, 2018, 03:46:22 am
Yes

Care to elaborate?
Look at what I wrote above. 
Title: Re: UK solar doldrums
Post by: lewis on January 14, 2018, 03:49:26 am
Look at what I wrote above.

Perhaps you can help me out a bit more than that! Which part of my post was wrong?

I suggest reading it again.
Title: Re: UK solar doldrums
Post by: lewis on January 14, 2018, 04:03:51 am
Yes I know that 1Wh is not 3600W I was just trying to emphasis the confusion that can arise.

You said:

Quote
if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.
I think you're confusing yourself!


If you were to say that this thing uses 1W anyone would assume you are saying it is a 1Wh device...
No. A 1W thing is not a 1Wh device:

A 1W thing, if left on for 1 minute, uses 0.0167Wh of energy
A 1W thing, if left on for 30 minutes, uses 0.5Wh of energy
A 1W thing, if left on for 1 hour, uses 1Wh of energy
A 1W thing, if left on for 10 hours, uses 10Wh of energy
A 1W thing, if left on for 1 year, uses 8760Wh of energy


...and yes in an instant, or second it will have 1W going into it.

A 1W load has 1W going into it for 1 second
A 1W load also has 1W going into it for 1/2 second
A 1W load also has 1W going into it for 1 nanosecond
A 1W load still has 1W going into it even for 1 picosecond
A 1W load also has 1W going into it for 1000 years

The power (watts) of a constant load does not change depending on time.
The energy (joules or watt-hours) DOES change depending on time.
Title: Re: UK solar doldrums
Post by: coppice on January 14, 2018, 04:26:09 am
if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.
One of the very first things they would have taught you in high school science is that units must match across an equals sign, so what you wrote there is bogus. 1Wh = 3600W is the most blatant garbage any 11 year old with an IQ around average should know is wrong, even if they struggle to figure out what is right.

Try something that keeps the units in good shape, like:

1Wh = 3600Ws = 3600J
Title: Re: UK solar doldrums
Post by: ahbushnell on January 14, 2018, 04:32:09 am
if 1W = 1J/s then 1Wh = 3600W = 3600 J/s.
One of the very first things they would have taught you in high school science is that units must match across an equals sign, so what you wrote there is bogus. 1Wh = 3600W is the most blatant garbage any 11 year old with an IQ around average should know is wrong, even if they struggle to figure out what is right.

Try something that keeps the units in good shape, like:

1Wh = 3600Ws = 3600J
It's good to know someone is learned in physics class.  :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 14, 2018, 05:36:20 am
Shame really what I started as I light hearted thread about the poor weather for PVers seems to have become a spat about units by people (going by the survey) who have nothing to do with PV anyway!

Maybe this site has a lot of bored people who like nothing better than hijacking threads for a good argument  :-BROKE
Title: Re: UK solar doldrums
Post by: Simon on January 14, 2018, 06:57:56 am
Sorry, seems some do like to pick up and pick holes in things that in the context were pretty self explanatory.
Title: Re: UK solar doldrums
Post by: tggzzz on January 14, 2018, 08:08:22 am
Sorry, seems some do like to pick up and pick holes in things that in the context were pretty self explanatory.

Possibly to the writer, but not to me (and maybe other readers).

I find statements like "London is 63mph away" or "speed when travelling to London is 150miles" to be confusing.

I would have thought a simple (i.e. easily correctable) mistake had been made; I'm surprised there has been all this discussion.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 14, 2018, 08:49:21 am
TGGZZZ I would say to those of who are involved in renewable energy and have a genuine interest it was perfectly obvious.

To those who seem to enjoy picking holes in things being said on threads they have nothing to do with and obsfucating the thread for no other purpose than some inane self satisfaction I wish to hell you would firstly desist and secondly bugger off somewhere else!!
Title: Re: UK solar doldrums
Post by: ahbushnell on January 14, 2018, 08:57:00 am
TGGZZZ I would say to those of who are involved in renewable energy and have a genuine interest it was perfectly obvious.

To those who seem to enjoy picking holes in things being said on threads they have nothing to do with and obsfucating the thread for no other purpose than some inane self satisfaction I wish to hell you would firstly desist and secondly bugger off somewhere else!!
So you don't think people should use watts and joules correctly?  It's a very basic concept. 
Title: Re: UK solar doldrums
Post by: tggzzz on January 14, 2018, 09:07:12 am
TGGZZZ I would say to those of who are involved in renewable energy and have a genuine interest it was perfectly obvious.

If it was obvious then a simple explanation would have avoided all this long discussion. The long discussion indicates that it was not obvious to many participants.

I am interested in renewable energy, both personally and because it is of vital importance to our children -- I want to see it succeed. To that end I have frequently been to professional meetings about the subject; the next one is on the 18th January. However Ill have to re-check whether it has been pre-empted by some recent developments.

I want to see hard numbers and well-reasoned arguments; like others I am frustrated by the "hot air" and "obfuscation" that often accompanies the subject.

I have no idea what a "non-genuine" interest might be.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 16, 2018, 04:51:55 am
I wish to unreservedly apologise for my earlier comments, although they may have been called for the language was intemperate to say the least.
Title: Re: UK solar doldrums
Post by: tggzzz on January 16, 2018, 05:27:48 am
I wish to unreservedly apologise for my earlier comments, although they may have been called for the language was intemperate to say the least.

Apology accepted. We all make mistakes, and the test is what happens thereafter :)

Never did manage to convince my daughter I was perfect :(

Besides, sometimes a strongly expressed difference of opinion is entirely appropriate, and we shouldn't be too hung up about slightly offending people. I'm sure we have all met people for whom http://dilbert.com/strip/2018-01-08 (http://dilbert.com/strip/2018-01-08) is warranted.
Title: Re: UK solar doldrums
Post by: stj on January 16, 2018, 10:02:06 am
here is an interesting thought.

*if* you could gather evidence showing who was behind chemtrail spraying in a specific country,
could you drag them into court for a class-action on bahalf of solar users??
Title: Re: UK solar doldrums
Post by: NiHaoMike on January 16, 2018, 04:35:24 pm
Where's the "my solar setup doesn't have an inverter" option?

I only do occasional checks with a clamp meter just to make sure there's no problems with the system. The exact amount of power coming out of the panel is not that important. What is tracked more often are the altcoins coming out of the miners (powered by the solar setup), since that's what my best friend and I really care about.
Title: Re: UK solar doldrums
Post by: nfmax on January 16, 2018, 11:29:51 pm
I have a grid-tied inverter on a nominal 1.7kW system. For the last 6 years, I have been logging the generation meter pulses (1 pulse per Wh). While this has not been without hiccups, I have enough data to be able to generate the mean annual generation plot shown. This gives, for each day of the year and each 15 minute interval, the mean power generated by the array and delivered to the grid (i.e. subtracting the inverter losses). The colour scale shown is in kW. Overlaid on this plot is the position of the sun at every moment, in the form of a double contour plot. The green contour lines are elevation, the purple lines azimuth.

This shows up the shading which limits the afternoon/evening performance of the array, and the surprising* variability of the weather, even in the summer. Also, how dire the winter performance is at this latitude!

From the sun contour plots, you should be able to work out roughly where this array is located...

*Only really surprising to people who don't live in the UK.
Title: Re: UK solar doldrums
Post by: ahbushnell on January 17, 2018, 03:23:06 am
This shows up the shading which limits the afternoon/evening performance of the array, and the surprising* variability of the weather, even in the summer. Also, how dire the winter performance is at this latitude!

From the sun contour plots, you should be able to work out roughly where this array is located...

Very cool plat. 
Title: Re: UK solar doldrums
Post by: BradC on January 17, 2018, 04:03:24 am
*Only really surprising to people who don't live in the UK.

I don't live in the UK, but I've spent enough time there to grok it.

I will say that is (in the language of my 3 year old) "10 times awesome". It's rare to see such a large amount of data presented in a format that makes the intended view so obvious. It really is 10 times awesome.
Title: Re: UK solar doldrums
Post by: nfmax on January 17, 2018, 05:38:48 am
I will say that is (in the language of my 3 year old) "10 times awesome". It's rare to see such a large amount of data presented in a format that makes the intended view so obvious. It really is 10 times awesome.

Aww, thanks! This kind of data presentation, and wrangling the raw outputs from sensors into something presentable, is more or less what I do for a living these days. I used to be an electronics engineer...
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 17, 2018, 05:57:56 am
I have a grid-tied inverter on a nominal 1.7kW system. For the last 6 years, I have been logging the generation meter pulses (1 pulse per Wh). While this has not been without hiccups, I have enough data to be able to generate the mean annual generation plot shown. This gives, for each day of the year and each 15 minute interval, the mean power generated by the array and delivered to the grid (i.e. subtracting the inverter losses). The colour scale shown is in kW. Overlaid on this plot is the position of the sun at every moment, in the form of a double contour plot. The green contour lines are elevation, the purple lines azimuth.

This shows up the shading which limits the afternoon/evening performance of the array, and the surprising* variability of the weather, even in the summer. Also, how dire the winter performance is at this latitude!

From the sun contour plots, you should be able to work out roughly where this array is located...

*Only really surprising to people who don't live in the UK.
Woww that is an astonishing data presentation, so many axis intelegbly displayed, I guess it helps that mother earth has related them all in a nice order :) As for the performance at this lattitude I think we are at the limit's of financial viablity (without subsidy) for DIY systems (IMOP). Am I being stupid or are you about 10 degrees further north than me (I am 52deg) ?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 17, 2018, 06:04:20 am
Where's the "my solar setup doesn't have an inverter" option?

I only do occasional checks with a clamp meter just to make sure there's no problems with the system. The exact amount of power coming out of the panel is not that important. What is tracked more often are the altcoins coming out of the miners (powered by the solar setup), since that's what my best friend and I really care about.
I do apologize it ran out of options after five and I already put in the easy ones :) First time I tried a poll.
Yours is an interesting use of solar energy, I am not sure where it fit's on the saving the planet scale as it's like doing something we don't need to live but them some would argue that keeping me alive is also a waste of energy!
Title: Re: UK solar doldrums
Post by: nfmax on January 17, 2018, 06:08:46 am
Am I being stupid or are you about 10 degrees further north than me (I am 52deg) ?
About 50.94 degrees N
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 17, 2018, 06:11:45 am
The clag lifted a little today and I got 1.4 EUEU'ts, average for the last week prior to today 0.1 EUEU'ts.
Please note an EUEU is an Ebonian Universal Energy Unit apparantly invented to avoid disputes or misunderstandings with there neighbors :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 17, 2018, 06:17:05 am
Am I being stupid or are you about 10 degrees further north than me (I am 52deg) ?
About 50.94 degrees N
Isnt that in the English channel or Irish sea :) (Guess I can't work out the azmuth) ?
Title: Re: UK solar doldrums
Post by: NiHaoMike on January 17, 2018, 01:21:41 pm
I do apologize it ran out of options after five and I already put in the easy ones :) First time I tried a poll.
Yours is an interesting use of solar energy, I am not sure where it fit's on the saving the planet scale as it's like doing something we don't need to live but them some would argue that keeping me alive is also a waste of energy!
I do proudly say that the positive impact of just that one solar panel was felt around the world. It is also important to note that because my mining setup is very efficient, it doesn't even use the full output of the panel. What's left over runs my other IT equipment.
Title: Re: UK solar doldrums
Post by: ahbushnell on January 17, 2018, 04:30:57 pm
I do apologize it ran out of options after five and I already put in the easy ones :) First time I tried a poll.
Yours is an interesting use of solar energy, I am not sure where it fit's on the saving the planet scale as it's like doing something we don't need to live but them some would argue that keeping me alive is also a waste of energy!
I do proudly say that the positive impact of just that one solar panel was felt around the world. It is also important to note that because my mining setup is very efficient, it doesn't even use the full output of the panel. What's left over runs my other IT equipment.
How long will it take to pay for it with bit coins? 
Title: Re: UK solar doldrums
Post by: NiHaoMike on January 17, 2018, 06:06:44 pm
How long will it take to pay for it with bit coins? 
Altcoins are not the same as Bitcoin. That setup (4 smartphones, 2 tablets, and a small ASIC) was actually making a very good profit of nearly $150/month until the difficulty went up. Now it's doing about $45/month.

The real gain for me, though, is that all my friends were really impressed with what I do with technology. And that I'm helping to make the world a better place.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 17, 2018, 10:30:49 pm
Altcoins are not the same as Bitcoin. That setup (4 smartphones, 2 tablets, and a small ASIC) was actually making a very good profit of nearly $150/month until the difficulty went up. Now it's doing about $45/month.

The real gain for me, though, is that all my friends were really impressed with what I do with technology. And that I'm helping to make the world a better place.
Thats an amazing system and much better than burning fossil fuels to do it as I have heard some are doing on an industrial scale! I found out it's easy to add a 6th option to the vote for non-GTI systems as was mine till recently :) Of course the variations on a PV system are endless I was trying to keep it not too techy :)
Title: Re: UK solar doldrums
Post by: IanMacdonald on January 19, 2018, 02:03:28 am
I do have a couple of panels I use for battery charging, but in a UK January forget it. Only a tenth of summer output.
Title: Re: UK solar doldrums
Post by: metrologist on January 19, 2018, 02:59:54 am
only 78Wh yesterday.
Title: Re: UK solar doldrums
Post by: ahbushnell on January 19, 2018, 11:17:26 am
only 78Wh yesterday.

What fraction of the year do you get "usable" power? 
Title: Re: UK solar doldrums
Post by: metrologist on January 19, 2018, 03:55:17 pm
don't know, just tossed it out on the patio table a few months ago. I've not been keeping records either, just casual glances at the watt meter - 158Whr today. Solar insolation here is generally 4.5.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 19, 2018, 05:51:24 pm
Well don't despair entirely in January I have done better the last few day's allowing the weekly rolling average to lift to a dizzying 0.6Units per day so far this week :) Long may it continue!
Title: Re: UK solar doldrums
Post by: metrologist on January 20, 2018, 02:29:20 am
I just have it connected to a tired old FLA. I'm not sure if my SCC does the right charge cycles so I may consider monitoring that somehow. I set the terminate voltage to 13.5 and it looks like the SCC just goes to a trickle charge at that voltage. It does let me select one of three difference LA battery types, so it must be doing something different for each one.
Title: Re: UK solar doldrums
Post by: splin on January 22, 2018, 05:52:29 am
The OP's sunshine shortage is not an isolated incident.

Quote
Sunshine is in short supply across a swathe of north-west Europe, shrouded in heavy cloud from a seemingly never-ending series of low pressure systems since late November and suffering one of its darkest winters since records began

It's not just the UK.

Quote
Belgium’s Royal Meteorological Institute has declared December 2017 “the second darkest month since 1887”, when it began measuring, after the 10.5 hours of sun recorded at its Uccle weather station last month were beaten only by a bare 9.3 hours in 1934.

From https://www.theguardian.com/world/2018 (https://www.theguardian.com/world/2018)

It does highlight the problem with large scale PV in these northern climes; lots of power in midsummer when demand is lowest and b*gger all in winter when it's needed most. And it doesn't help that inter-seasonal storage is hellishly expensive - perhaps the only viable option being synthesised liquid fuels, or possibly gas for which long term storage costs aren't totally out of reach. Unfortunately, I understand the cost and efficiency of the synthesis processes are very poor.

The interesting question (to me) is should PV play any worthwhile role in these low insolation regions if renewables are to reach close to 100% of total generation? In winter the only viable source is wind. But if you have enough turbines to cover winter, alongst with short term storage (and FF backup for the occasional one or two week doldrums that can cover much of Europe) then you likely have more than enough wind generation in summer as well - average wind speeds may be lower than winter but demand is also much lower.

So why bother with PV? It obviously would be useful supplying power when there is no wind but the economics would be terrible - the viability of PV in the UK at present is predicated on being able to sell all the annual generation at reasonable prices which would not be available for large parts of the year when the wind is blowing.

[Edit] Fixed typos.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 22, 2018, 09:07:56 am
It does highlight the problem with large scale PV in these northern climes; lots of power in midsummer when demand is lowest and b*gger all in winter when it's needed most. And it doesn't help that inter-seasonal storage is hellishly expensive - perhaps the only viable option being synthesised liquid fuels, or possibly gas for which long term storage costs aren't totally out of reach. Unfortunately, I understand the cost and efficiency of the synthesis processes are very poor.
My intention was to keep the post to personal or small scale systems as a whole new dimension of issues apply at a national level that I think have been discussed elsewhere.  As for wind or water power I am not gifted in location and in any case small scale wind is sadly outlawed by planning requirements for those with a normal sized garden.
Title: Re: UK solar doldrums
Post by: metrologist on January 23, 2018, 07:25:50 am
I also wanted to install a small wind generator. We get a stiff breeze many afternoons, but I'll have to check the regulations on it.

My panel is in a poor spot, blocked in the AM by clouds/fog and noon hours by building and tree. I get full sun on it starting about 1pm. I moved it and set it up more perpendicular to the sun and managed a 250Wh day.

There is this new global darkening I hear now?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 23, 2018, 05:55:20 pm
I also wanted to install a small wind generator. We get a stiff breeze many afternoons, but I'll have to check the regulations on it.

My panel is in a poor spot, blocked in the AM by clouds/fog and noon hours by building and tree. I get full sun on it starting about 1pm. I moved it and set it up more perpendicular to the sun and managed a 250Wh day.

There is this new global darkening I hear now?
If your in the uk the rule is base must be at least as far from any boundary as the tower height plus blade length, that pretty well knackers you from getting up enough to avoid ground turbulance and building/tree shadow in most domestic gardens :(

Thats a pretty good result for solar, I got 1.1U yesterday and the monthly average finaly lifted from 0.3U/day to 0.4!!

I guess your talking about atmospheric pollution rather than the sun going out :)
Title: Re: UK solar doldrums
Post by: paulca on January 23, 2018, 06:58:47 pm
Tehe.

I averaged about 120mW power yesterday with the odd spike to 300mW.

It's an indoor 50W system though.  Saturday was different.  I got quite a long period of 15-25W.
Title: Re: UK solar doldrums
Post by: grifftech on January 24, 2018, 04:49:08 am
I have solar, but it is a 6vdc system
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 24, 2018, 05:46:30 am
Tehe.

I averaged about 120mW power yesterday with the odd spike to 300mW.

It's an indoor 50W system though.  Saturday was different.  I got quite a long period of 15-25W.
Perhaps you forgot to draw the curtains yesterday! Good today though :)
Some days with my 1Kw outdoor system you would think it's covered in curtains too, maybe 15W if lucky so 1.5%! Don't you count as a no GTI but keep records man in the survey ?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 24, 2018, 05:48:23 am
I have solar, but it is a 6vdc system
It all counts, mine pushes DC (sometimes a bit chopped) into the hot water tank heater and only converts to AC to use any surpless from that.
Title: Re: UK solar doldrums
Post by: paulca on January 24, 2018, 05:50:47 am
Perhaps you forgot to draw the curtains yesterday! Good today though :)
Some days with my 1Kw outdoor system you would think it's covered in curtains too, maybe 15W if lucky so 1.5%!

It's in my vampire cave, but it's on the daylight side of the curtains.

Haven't looked at today's graph, no point.  The sun did come out briefly at one point, but the battery voltage moved from 12.1 to 12.2. 

And my last downstream lithium just low voltage alarmed. :(
Title: Re: UK solar doldrums
Post by: paulca on January 24, 2018, 05:59:07 am
I know this is UK, but I'm up at 54.5* North.  It's only just got to being barely daylight when I leave for work at 8:20am and there was a tiny hint of light in the sky at 5:00 when I left for home.  :(  I hate this time of year.

Of course in June it's the other way.
Title: Re: UK solar doldrums
Post by: paulca on January 24, 2018, 06:10:40 am
Hmmm.   The graph suggests it did okay.

(http://i.imgur.com/wwOrM9b.png) (https://imgur.com/wwOrM9b)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 24, 2018, 06:22:28 am
Hey cool paul, is that a PI ?

I collect mine with a PIC in an EEPROM for dynamic display on an LCD and only periodically dump the data to produce a graph on the PC, my last looked like this to the beginning of December and I know from the LCD it got down to 0.3U/day late Dec / early Jan. Horizontal axis is hours, vertical is unit's per day and its rolling averaged over 7 days.
Going by the LCD display things are at last picking up again so guess I will do another dump and new graph beginning of Feb.

Of course cannot wait for summer, hoping to drive my big outdoor woodsaw from it this year :)
Title: Re: UK solar doldrums
Post by: paulca on January 24, 2018, 06:59:10 am
Hey cool paul, is that a PI ?

Kinda.  It's a PI and an ESP8266.  This more or less:

http://www.eevblog.com/forum/projects/nodemcu-esp8266-rs485-epever-solar-monitor-diy/ (http://www.eevblog.com/forum/projects/nodemcu-esp8266-rs485-epever-solar-monitor-diy/)
http://www.eevblog.com/forum/beginners/finally-got-my-first-project-actually-complete/ (http://www.eevblog.com/forum/beginners/finally-got-my-first-project-actually-complete/)

It's moved on a bit.  I now have the RRDs automated, 1 once per minute for all data.  Graphs are done by rrdgraph (https://oss.oetiker.ch/rrdtool/gallery/index.en.html).

It's a bit "how you doing" at the moment.  It all works, but it's kinda like breadboard.  I have to log in and run commands to generate graphs.  I hope to make it generate them daily and create web pages for each group of data.

Graphs could be prettier too.  The RRA databases contain data for 10 years and can produce daily, weekly, monthly, yearly graphs or any time window or parameters you want.  Multiple data sources can be overlayed, stacked etc.  There are web UIs for it, I might resort to one for convenience.
Title: Re: UK solar doldrums
Post by: Blocco on January 24, 2018, 07:45:31 pm
I also wanted to install a small wind generator. We get a stiff breeze many afternoons, but I'll have to check the regulations on it.


If your in the uk the rule is base must be at least as far from any boundary as the tower height plus blade length, that pretty well knackers you from getting up enough to avoid ground turbulance and building/tree shadow in most domestic gardens :(



I wonder whether the same regulations apply to mobile structures i.e. a mast mounted on a trailer or vehicle.
Title: Re: UK solar doldrums
Post by: paulca on January 25, 2018, 12:07:23 am
Today looks like a cracker over here in Northern Ireland.  It's been 5-10% cloud all day so far.

https://www.windy.com/?clouds,54.615,-5.713,10,m:fcfafZG (https://www.windy.com/?clouds,54.615,-5.713,10,m:fcfafZG)

Does anyone know where you can get "sun" power levels on a weather forecast?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 25, 2018, 06:57:20 pm
I also wanted to install a small wind generator. We get a stiff breeze many afternoons, but I'll have to check the regulations on it.


If your in the uk the rule is base must be at least as far from any boundary as the tower height plus blade length, that pretty well knackers you from getting up enough to avoid ground turbulance and building/tree shadow in most domestic gardens :(



I wonder whether the same regulations apply to mobile structures i.e. a mast mounted on a trailer or vehicle.
I assume you mean pseudo mobile as in stuck in your garden then yes and frankly the guy's would have to be at a greater radius than a road vehicle. If you mean a 20ft mast on a road going vehicle I think your chances of getting down your road before being pulled up by the police are nill.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on January 25, 2018, 07:01:35 pm
Today looks like a cracker over here in Northern Ireland.  It's been 5-10% cloud all day so far.

https://www.windy.com/?clouds,54.615,-5.713,10,m:fcfafZG (https://www.windy.com/?clouds,54.615,-5.713,10,m:fcfafZG)

Does anyone know where you can get "sun" power levels on a weather forecast?
Not seen it, I just go by the cloud cover given in https://www.netweather.tv/weather-forecasts/uk/today/2520~((%20Belfast%20))#forecast (https://www.netweather.tv/weather-forecasts/uk/today/2520~((%20Belfast%20))#forecast) for example and your place doesnt look to good today while mine is cool :)

Thanks so much for the links to the software, makes my efforts using GnuPlot look primative!
Title: Re: UK solar doldrums
Post by: paulca on January 25, 2018, 07:11:57 pm
Thanks so much for the links to the software, makes my efforts using GnuPlot look primative!

No problem.  The easier solution is to install a linux distro's version of "Cacti" and hack in a datasource for whatever you want.  Usually just a script based one.  Cacti takes care of the rest, although it can be a bit fiddly at first understanding the different names for things.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 01, 2018, 02:48:13 am
Things are slowly picking up here in the new year :) I just dumped this primative chart in units/day averaged over a week, bottom scale is hours.
Title: Re: UK solar doldrums
Post by: paulca on February 01, 2018, 04:04:44 am
Things are slowly picking up here in the new year :) I just dumped this primative chart in units/day averaged over a week, bottom scale is hours.

I'm going to try and produce some graphs to work out if my system is consuming more internally than it's actually producing on grey days :(  Yes it's that bad here.  Monday was a cracker though.  Tuesday and today, rubbish.  Days are getting longer though.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 01, 2018, 06:51:37 am
to work out if my system is consuming more internally than it's actually producing
I have two things powered by the grid in the solar system (running 24/7), one is the data logger and the other is the grid import/export power measurer and together they consume 1100mW.

I am guilty of using lots of cheap USB power supplies around the house for powering gadgets and most of them consume >500mW each with no load :( One day I might install a low power low voltage buss (say 12) just for the gadgets! I used to have some guided missile wire (almost invisable) that would have been ideal but it vanished completely in various house moves  :-DD
Title: Re: UK solar doldrums
Post by: nfmax on February 08, 2018, 07:42:58 am
3.842 kWh today! The sun is coming back!  :)
Title: Re: UK solar doldrums
Post by: paulca on February 08, 2018, 08:15:35 am
Nothing today.  Anything I did get got used by the charge controller :(  Doesn't look like we will get sun until Friday and even then it's a few hours.  My panel only produces a decent amount between 10am and 1pm.  The joys of having a panel in a window.

Still, it's meeting demands for charging USB devices, running my bench supply and running my headphone amp.  Basically anything I can run off 12V battery on my desk.  I can even run a 3W LED lightbulb or two when I feel like it.

I call it NanoGen.
Title: Re: UK solar doldrums
Post by: nfmax on February 17, 2018, 07:31:26 am
3.898 kWh today
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 17, 2018, 06:09:30 pm
3.898 kWh today
Yeyy the sun is coming back, my average weekly finally hit 1Kwh/day after a winter low of 0.3Kwh/day from a 1Kwe array. How many Kwe is yours, 4 ?
Title: Re: UK solar doldrums
Post by: paulca on February 17, 2018, 08:27:03 pm
I also got a load this week.  All my batteries are topped up.  Each evening I end up running the battery down to 12.1 or 12.2 and come home to it up at 12.6 or 12.7. I might let it fully charge some day, but I expect in summer that will easy.

So far I've hit a peak, from a 50W panel, of 28W.  For a panel behind a window this has to be good.
Title: Re: UK solar doldrums
Post by: nfmax on February 18, 2018, 12:50:55 am
3.898 kWh today
Yeyy the sun is coming back, my average weekly finally hit 1Kwh/day after a winter low of 0.3Kwh/day from a 1Kwe array. How many Kwe is yours, 4 ?
1.71 kWp, according to the installation certificate.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 18, 2018, 03:26:25 am
Wowww thats a really good result. Mine is 1060We/p but at this time of year I am not able to use all of a good day as the boiler is still heating the water a bit due to central heating and I don't use enough electricity! Tried today by shredding loads of compost and using the hedge trimmer :)
Title: Re: UK solar doldrums
Post by: paulca on February 18, 2018, 03:48:33 am
Solar energy storage is the future.  I wonder if micro-hydro works if you don't like batteries.  Probably not :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 18, 2018, 03:55:11 am
Solar energy storage is the future.  I wonder if micro-hydro works if you don't like batteries.  Probably not :)
Hey cool idea, I actually have a stream with almost zero fall/head, I could build a pond further up the garden but I think the frost will be a problem as well as a dual purpose pump/turbine! Never mind I continue to use the grid as my battery! To me it's all about contribution, like that retailer slogan "every little helps" :)
Title: Re: UK solar doldrums
Post by: nfmax on February 24, 2018, 04:31:11 am
And a whopping 5.264 kWh today! Cold, sunny & cloudless
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 24, 2018, 07:19:18 am
Wowww well done, weather not so good here so just 0.8Kwh today  :-[ but over 2Kwh couple of days ago :)
Title: Re: UK solar doldrums
Post by: nfmax on February 25, 2018, 04:49:13 am
Today we got 5.396 kWh. One more sunny day forecast, then cloud & possible snow
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 25, 2018, 05:21:37 am
1.9Kwh today on a 1Kw array, still held back by terrible Fronious software, drops out all the time and has 5 minute restart delay but hey it will be in the bin soon I hope :) so most of my load is water heating atm. Your figures really are very good sure your really in the UK hahaha
Title: Re: UK solar doldrums
Post by: paulca on February 25, 2018, 08:11:49 am
I need to move house and get better panels.

Today I started with 12.0V on the battery and ended with 11.9V.  Took more to run the charge controller and 485 Wifi monitor than I actually got from the sun.  It was a pretty dark and miserably day though.
Title: Re: UK solar doldrums
Post by: John Heath on February 25, 2018, 07:22:32 pm
 I have a solar power system. It is home brew with a 2 by 2 inch solar cell and a nicad power storage capacity of 200 ma at 1.2 volts. This power is automatically used at night to light a single white IR type white LED , 1 volt 20 ma. The reason was to back light an outside temperature gauge so it can be seen at night. All went well for the winter with 3 to 4 hours of a solar powered back lighting. However in the summer the LED attracted small flies. This did not escape the attention of the local spiders who soon set up camp on my solar power system. Not sure what they did but the white LED no longer shines at night. Easier to build another as all the part are in a 4 dollar back yard garden light sold in most stores. I guess my point is even micro solar power systems have their problems. The best laid plans...
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 25, 2018, 08:25:43 pm
I need to move house and get better panels.

Today I started with 12.0V on the battery and ended with 11.9V.  Took more to run the charge controller and 485 Wifi monitor than I actually got from the sun.  It was a pretty dark and miserably day though.
Just start by getting it outside and faceing south :) Simple wooden frame on the ground and use the battery to weight it down ?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 25, 2018, 08:29:47 pm
I have a solar power system. It is home brew with a 2 by 2 inch solar cell and a nicad power storage capacity of 200 ma at 1.2 volts. This power is automatically used at night to light a single white IR type white LED , 1 volt 20 ma. The reason was to back light an outside temperature gauge so it can be seen at night. All went well for the winter with 3 to 4 hours of a solar powered back lighting. However in the summer the LED attracted small flies. This did not escape the attention of the local spiders who soon set up camp on my solar power system. Not sure what they did but the white LED no longer shines at night. Easier to build another as all the part are in a 4 dollar back yard garden light sold in most stores. I guess my point is even micro solar power systems have their problems. The best laid plans...
That's so funny I have thousands of spiders BUT they refuse to make home in the solar converters, maybe being chopped up by fans, roasted on heatsinks, burnt on 500V terminals and deafened by shreiking 25Khz ferrites doesnt suit them  >:D
Title: Re: UK solar doldrums
Post by: paulca on February 25, 2018, 08:43:45 pm
I need to move house and get better panels.

Today I started with 12.0V on the battery and ended with 11.9V.  Took more to run the charge controller and 485 Wifi monitor than I actually got from the sun.  It was a pretty dark and miserably day though.
Just start by getting it outside and faceing south :) Simple wooden frame on the ground and use the battery to weight it down ?

1st (and 2nd) floor apartment.  If I carted it up stairs I could hang it out the skylight onto the roof, but with no way to fix it in place without consulting the landlord it would be "under supervision" on calm days only.   I might do this the next blue sky day to see if I can get the full 50W.

In it's south facing window the most it has produced so far is around 28W.

The charge controller hasn't even clocked to 2kWh and it's been running for over a month now. :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 26, 2018, 03:33:14 am
1st (and 2nd) floor apartment.  If I carted it up stairs I could hang it out the skylight onto the roof, but with no way to fix it in place without consulting the landlord it would be "under supervision" on calm days only.   I might do this the next blue sky day to see if I can get the full 50W.
In it's south facing window the most it has produced so far is around 28W.
The charge controller hasn't even clocked to 2kWh and it's been running for over a month now. :)
Ahh ok, well I hate to suggest polishing the window both sides as maybe you have already done that but I did see someone using baco-foil reflectors with a small panel to improve output!
Title: Re: UK solar doldrums
Post by: jc101 on February 26, 2018, 05:31:31 am
Best day of the year today, managed to get 9.99kWh from our 2.57kW array.

Strategic use of dishwasher, washing machine, and drier has meant that only ~20% was exported today.
Title: Re: UK solar doldrums
Post by: paulca on February 26, 2018, 05:38:27 am
I had an interesting experience today.  It might be hard to explain... or you will understand straight away and berate me for not knowing....

When the sun is directly in front of the panel  around noon (through a window), leaning it back slightly to "look up at the sun" and get a more direct perpendicular angle, produces a little more current.  This seem intuitive and obvious.  We are talking about producing 23W and leaning to back 10 degrees produces 25W.

However at 2pm when the sun is off to the side a little (not much) the output fall dramatically.  From around 25W to around 6W.

I found this annoying, so I played with the position and found that pointing the panel directly at the sun produced very little output - 5-7W.

Pushing the panel tight against the window and completely off axis with the sun produced the highest output.  20W.

I conclude that the insulation through a window is HIGHLY dependant on the angle of incidence between the panel and the window and less on the angle of the sun and the panel.

EDIT: I think the relationship is the intuitive; "on axis" to the sun is better.  However, loss through the window at an angle is huge, so an off axis panel produces more output than an on axis panel with an angular offset trough glass.  Outdoors the window is removed and an on-axis panel alignment will always win.
Title: Re: UK solar doldrums
Post by: John Heath on February 26, 2018, 05:49:01 am
I have a solar power system. It is home brew with a 2 by 2 inch solar cell and a nicad power storage capacity of 200 ma at 1.2 volts. This power is automatically used at night to light a single white IR type white LED , 1 volt 20 ma. The reason was to back light an outside temperature gauge so it can be seen at night. All went well for the winter with 3 to 4 hours of a solar powered back lighting. However in the summer the LED attracted small flies. This did not escape the attention of the local spiders who soon set up camp on my solar power system. Not sure what they did but the white LED no longer shines at night. Easier to build another as all the part are in a 4 dollar back yard garden light sold in most stores. I guess my point is even micro solar power systems have their problems. The best laid plans...
That's so funny I have thousands of spiders BUT they refuse to make home in the solar converters, maybe being chopped up by fans, roasted on heatsinks, burnt on 500V terminals and deafened by shreiking 25Khz ferrites doesnt suit them  >:D

Electrocution or the nasty indifference of a spinning fan is a little much. We all have to get by in life and I have nothing against spiders.  I just want them away from the micro solar power plant. I am liking the sounds of the shrieking 25 KHz ferrite , pun intended. Bats hunt insects so I imagine most insects would find the ultrasonic chirps of a bat alarming. A low powered PIC programmed to make the ultrasonic sound of a chirping hungry bat every 60 seconds.  This should keep then too nervous to call this home for a good 12 inches around the solar power system. Somewhat like hocks near an airport to keep the birds away. Micro solar power plant 2 should have bat simulated sounds. This would be a chance to home some skills in PIC low power applications. With the addition of smart PIC the micro solar power plant could reach out into other energy sources , a tiny 2 inch fan for those windy days.     
Title: Re: UK solar doldrums
Post by: paulca on February 26, 2018, 05:57:52 am
Best day of the year today, managed to get 9.99kWh from our 2.57kW array.

Strategic use of dishwasher, washing machine, and drier has meant that only ~20% was exported today.

While I understand that batteries for that kind of through put are difficult.  Does it not make you think that some sort of storage solution would be beneficial?  I know that I, like many people, are out during the day 5 days a week.  Power requirements for half the year (at these latitudes) are minimal when you are out at work (The whole "solar power day").

For Northern Ireland at 54* North solar without storage would be next to pointless.  Of course the investment companies don't see it that way.  They see the advantage.  They charge you a meer deposit of a few thousand pounds and put 3kw of panels on your roof.  You get to use whatever you want and the rest gets exported to the grid.  But the market is young professionals who are out all day.  They think they are doing their bit for the environment, but really they are doing their bit for the investment banks who fund their panels.

The panels might produce 10kwh that they don't use at a rate of 3p.  But you get none of that on these schemes.  It apparently works out that it's a money maker for the investment banks who have sold decades of energy futures based on it... then dumped the products to the next investor.

On such schemes you are forbidden to install a storage solution as it will directly impact the investors profit...

... or I am exaggerating and the reality is less severe....
Title: Re: UK solar doldrums
Post by: ahbushnell on February 26, 2018, 01:13:41 pm
I had an interesting experience today.  It might be hard to explain... or you will understand straight away and berate me for not knowing....

When the sun is directly in front of the panel  around noon (through a window), leaning it back slightly to "look up at the sun" and get a more direct perpendicular angle, produces a little more current.  This seem intuitive and obvious.  We are talking about producing 23W and leaning to back 10 degrees produces 25W.

However at 2pm when the sun is off to the side a little (not much) the output fall dramatically.  From around 25W to around 6W.

I found this annoying, so I played with the position and found that pointing the panel directly at the sun produced very little output - 5-7W.

Pushing the panel tight against the window and completely off axis with the sun produced the highest output.  20W.

I conclude that the insulation through a window is HIGHLY dependant on the angle of incidence between the panel and the window and less on the angle of the sun and the panel.

EDIT: I think the relationship is the intuitive; "on axis" to the sun is better.  However, loss through the window at an angle is huge, so an off axis panel produces more output than an on axis panel with an angular offset trough glass.  Outdoors the window is removed and an on-axis panel alignment will always win.

As the sun get's lower in the sky the atmosphere blocks more solar radiation. 
Title: Re: UK solar doldrums
Post by: paulca on February 26, 2018, 07:02:32 pm
As the sun get's lower in the sky the atmosphere blocks more solar radiation.

Yes, that accounts for the drop from 25W to 20W, but not the drop to 6W which happens pretty quickly over the space of 30 minutes.
Title: Re: UK solar doldrums
Post by: capt bullshot on February 26, 2018, 07:23:22 pm
I've seen this thread only now - I'm keeping track of my solar power by some homebrew data logging stuff.
The public interface is here:
http://wc.wunderkis.de/webcam1.php (http://wc.wunderkis.de/webcam1.php)
(sorry, it's German labeled), the last chart is the kWh / installed kW of my solar panels.
So got a few really nice and sunny days after very dark December and January.

For my purposes (not available to the public), I've got more charts, like these telling me the amount of produced solar power and the ratio to power used by the household (daily for the last 30 days and over one year):
Title: Re: UK solar doldrums
Post by: paulca on February 26, 2018, 07:33:57 pm
Yah!  Another RRD Graph user :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 27, 2018, 06:49:41 am
As the sun get's lower in the sky the atmosphere blocks more solar radiation.

Yes, that accounts for the drop from 25W to 20W, but not the drop to 6W which happens pretty quickly over the space of 30 minutes.
I am wondering if this has something to do with diffraction through the glass or special glasses often used in double glazing (high iron content) is that possible ?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on February 27, 2018, 06:53:18 am
I've seen this thread only now - I'm keeping track of my solar power by some homebrew data logging stuff.
The public interface is here:
http://wc.wunderkis.de/webcam1.php (http://wc.wunderkis.de/webcam1.php)
(sorry, it's German labeled), the last chart is the kWh / installed kW of my solar panels.
So got a few really nice and sunny days after very dark December and January.

For my purposes (not available to the public), I've got more charts, like these telling me the amount of produced solar power and the ratio to power used by the household (daily for the last 30 days and over one year):

OK I can see my primative graphs with GNU look entirely out of date wrt you guy's so when we hit the end of the month and I suck some fresh data from the logger I will have to try RRD too :)
Title: Re: UK solar doldrums
Post by: ahbushnell on February 27, 2018, 09:55:31 am
As the sun get's lower in the sky the atmosphere blocks more solar radiation.

Yes, that accounts for the drop from 25W to 20W, but not the drop to 6W which happens pretty quickly over the space of 30 minutes.
The reflection coefficient on glass (or anything) changes with the angle of incidence by Fresnel's Law. 

https://www.brown.edu/research/labs/mittleman/sites/brown.edu.research.labs.mittleman/files/uploads/lecture13_0.pdf (https://www.brown.edu/research/labs/mittleman/sites/brown.edu.research.labs.mittleman/files/uploads/lecture13_0.pdf)

  I added a plot for glass of index 1.5.  Transmission starts to drop off around 50 degrees from normal.  Not sure the window reflection accounts for what you see.  Low angle sun going through thick air and more water vapor? 

This is interesting.
http://www.ecgllp.com/files/3514/0200/1304/2-Solar-Radiation.pdf (http://www.ecgllp.com/files/3514/0200/1304/2-Solar-Radiation.pdf)


Andy
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 02, 2018, 03:50:53 am
Things are definetly improving as the days get longer again, here is my weekly average output to date in Kwh/day, horizontal axis is elapsed hours (500hrs = 21Days) still in GNUplot  :-\
Title: Re: UK solar doldrums
Post by: paulca on March 02, 2018, 06:08:38 am
Not sure the window reflection accounts for what you see.  Low angle sun going through thick air and more water vapor? 

It could have been.  What surprised me was how sharp it fell.  I had the little query monitor open in a terminal on my desktop.  I could see the bright sunshine coming through the window (well a gap in the curtains), but the Panel Amps was really low.  So I went to investigate as it had been sitting happily around 1.8-2.0 amps from 10am through to 2pm.  Yet at 3pm it had fallen to like 0.5A.  Pushed the panel back up to the window and it went back up to 1.5A.

I've left it against the window, I might lose 10% or so in the morning when the sun is bang on, but it should keep the watts higher further into the afternoon.
Title: Re: UK solar doldrums
Post by: nfmax on March 03, 2018, 04:26:23 am
And today we had - nothing at all! Not an electronic sausage  :(

Clearly I need to add some snowlar panels
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 03, 2018, 05:05:12 am
And today we had - nothing at all! Not an electronic sausage  :(
Clearly I need to add some snowlar panels
To right but suprisingly mine have been hauling in up to 250W through 4 inches of white stuff!! (25% peak power).
Actually I seem to remember reading long ago that the poly panels I have are better at diffuse light than amorphous even though the latter have a bit more efficiency in full sun.
Title: Re: UK solar doldrums
Post by: paulca on March 03, 2018, 05:16:23 am
I lost energy today.  Another day costing more electrons running the charge controller than the panel produced.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 03, 2018, 05:22:57 am
Maybe pay some attention to the thirst of this charge controller, I spent a lot of time when I first started reducing the power needed to run converters to the barest minimium so my pickup light level was as low as possible. Not sure how much I really gained from it apart from the design excercise and being able to see my converters hang on in the evening right down to a measly 1 watt :)
Title: Re: UK solar doldrums
Post by: paulca on March 03, 2018, 06:58:01 am
I measured it.  50mA with pulses of 75mA when the ESP8266 fires the data out on the Wifi every 5 seconds.  <-- Should drop that back to once a minute.

Doesn't sound like much but when you multiply it (avg. 60mA) out to 24 hours, it's 1.4Ah.   

I switch the whole system off at night, so at the moment it's probably only about a third of that.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 03, 2018, 08:27:22 pm
One idea, are you using a switching or linear regulator to get from your battery voltage (13.8V?) to your mpu (3V3?) a switcher could save you a lot of power if it's reasonably efficient and I expect Ebay is loaded with the things ready built :)
Title: Re: UK solar doldrums
Post by: paulca on March 03, 2018, 08:58:33 pm
Switching MPPT DC/DC.  50mA/75mA isn't an awful lot to run a charge controller, it's LCD (no backlight) a RS485 to Serial adapter and an ESP8266 and a wifi client.

According to the controller it's efficiency is suspiciously near perfect.  If its showing panel power of 6.1W the battery charge watts show as 6.1W.

Still have to shorten the panel cable, or replace with some mains flex.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 04, 2018, 02:51:40 am
You just told me that was the consumption you measured sorry if I was wrong but the mpu supply doesnt need to have anything to do with MPPT surely it can just run off the battery I thought.

Maybe the reselution of measurement is such that it's internal consumption just doesnt show.

So your cables are still acting as room heaters ?
Title: Re: UK solar doldrums
Post by: paulca on March 04, 2018, 07:58:28 am
Yes :(  I was in homebase and lifted a 5 meter bundle of 15A mains wire, but set it down again when I read the price.  £12.99.  Ouch.

I'll order some on ebay, I have run out of "kettle leads" to salvage.  When you are looking for other cables there are fecking dozens of them, but when you are looking for power leads, you can't find any for USB leads and wall warts :(  The way it goes.

I mentioned the MPPT, DC/DC bit in case you thought it was a PWM duffer or linear regulator.

Yes the controller and monitor runs off the battery, but it doesn't seem to show internal load.  It registers watts and amps to 2 decimal places though, so it should.  However it does other weird things too. 

Over RS485 if you have 1Amp of solar, and 0.5Amp of load it will show:

Panel current: 1A
Battery current: 1A
Load current: 0.5A

There is a separate register for "Charge Current" which would read 0.5A.  It seems the battery sense is before the load gets split off.  On the panel LCD it does the sums though and subtracts the load from the battery current to be fairer.  Over RS485 you have to remember to do it yourself.
Title: Re: UK solar doldrums
Post by: Hero999 on March 04, 2018, 10:31:27 am
I believe solar panels are more efficient, at lower temperatures, because the voltage drop of the diode junction increases.

It's been cold in the UK recently, so has anyone noticed an increase in output, above what would be expected for the increase in day length? I suppose it's been cloudy recently so may be not. The MPPT also changes with temperature, so the inverter would need to monitor the temperature, in order to increase the efficiency of the panels, when they get cold.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 04, 2018, 08:14:53 pm
Yes :(  I was in homebase and lifted a 5 meter bundle of 15A mains wire, but set it down again when I read the price.  £12.99.  Ouch.

I'll order some on ebay, I have run out of "kettle leads" to salvage.  When you are looking for other cables there are fecking dozens of them, but when you are looking for power leads, you can't find any for USB leads and wall warts :(  The way it goes.

I mentioned the MPPT, DC/DC bit in case you thought it was a PWM duffer or linear regulator.

Yes the controller and monitor runs off the battery, but it doesn't seem to show internal load.  It registers watts and amps to 2 decimal places though, so it should.  However it does other weird things too. 

Over RS485 if you have 1Amp of solar, and 0.5Amp of load it will show:

Panel current: 1A
Battery current: 1A
Load current: 0.5A

There is a separate register for "Charge Current" which would read 0.5A.  It seems the battery sense is before the load gets split off.  On the panel LCD it does the sums though and subtracts the load from the battery current to be fairer.  Over RS485 you have to remember to do it yourself.
Ahh sorry of course it's all one lumped in unit with the charge controller, I had an idea you had a seperate MPU that you were powering. Seems like you are slowly learning this things quirks :) I agree on the cables I was looking for  a straight Ethernet the other day and all I could find were crossovers that are normally like rocking horse poo!!
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 04, 2018, 08:28:57 pm
I believe solar panels are more efficient, at lower temperatures, because the voltage drop of the diode junction increases.
Other way around a silicon junction voltage reduces at -2mV/degC.

It's been cold in the UK recently, so has anyone noticed an increase in output, above what would be expected for the increase in day length? I suppose it's been cloudy recently so may be not. The MPPT also changes with temperature, so the inverter would need to monitor the temperature, in order to increase the efficiency of the panels, when they get cold.

The whole point of MPPT is Tracking, so it adapts to changes in the maximium power point all by itself, this is the advantage of MPPT compared to some who claim constant voltage is adiquite!

Interestingly the plot thickens, when I checked the spec of the panels I use (enclosed) although Voc indeed has a negative coeficient Isc has a small posotive one but the overall Pmpp has a negative one!
Title: Re: UK solar doldrums
Post by: paulca on March 10, 2018, 09:10:28 am
How quickly things turn around.

I had resorted to mains power for charging my devices for a week.  Ran the solar battery down to 12.0V and watched it drop running just the charge controller to 11.8V over a week of snow and heavy cloud.

Wednesday this week the sun peeked  out once of twice and it rose back to 11.9V
Thursday the sun graced us for a few hours through broken cloud and it rose to 12.3V
Today it was sunny blue sky from 7am till 4pm and I came home to 12.8V, damn near full charged.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 10, 2018, 08:53:19 pm
How quickly things turn around.

I had resorted to mains power for charging my devices for a week.  Ran the solar battery down to 12.0V and watched it drop running just the charge controller to 11.8V over a week of snow and heavy cloud.

Wednesday this week the sun peeked  out once of twice and it rose back to 11.9V
Thursday the sun graced us for a few hours through broken cloud and it rose to 12.3V
Today it was sunny blue sky from 7am till 4pm and I came home to 12.8V, damn near full charged.
Maybe we can go into business selling the met office historical data to improve there forecasts :) Not to bad over here in the east but cloud cover at least every other day so averageing 1Kwh/day (from 1Kwe) ATM
Title: Re: UK solar doldrums
Post by: poida_pie on March 13, 2018, 12:31:50 pm
Here is my system's data from 1/1/2016 to date. I supply the house with some of it's energy needs from a 3kW solar array. I have a 18kWhr battery, and only cycle it about 6 kWh a day. Sometimes I can run large loads on solar AND charge the battery which explains the 15kWhr peaks in inverter energy.
Early Sept '17 the inverter died, hence zero energy during that period. Location is Melbourne, AUS.
You can see the seasonal dips and peaks.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 18, 2018, 10:12:52 pm
Hi Poida thats a great system :) Sure wish I was in Melbourne except maybe the hurricane! Do you have a make & model for the inverter or is it a DIY ?

I woke to ZERO POWER today, seems the panels are part snowbound and although the inverter happily reports zero watts it doesnt want to start and guess what, in minus4C I dont want to go out there with the laptop and pic debugger to ask it why hahaha
Most likely there is just enough voltage for the mpu to run but the 12V isnt solid enough (it checks that to ensure there is enough to turn the mosfets hard on).
Title: Re: UK solar doldrums
Post by: paulca on March 18, 2018, 11:56:35 pm
Hot water hose?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 19, 2018, 12:17:07 am
hahaha now if I lived on a ship I might just have one of those to hand :) maybe this is where keeping your panels indoors in the warm is a winner :)

EDIT interestingly just used summer washer (sponge on long stick) to wipe snow off lower 3rd of panels and output immediatly lept up to a respectable 100W or so. Lesson is oriantation of shadow is important to whether the shading diodes work or not!!
Title: Re: UK solar doldrums
Post by: Hero999 on March 19, 2018, 09:33:34 pm
I believe solar panels are more efficient, at lower temperatures, because the voltage drop of the diode junction increases.
Other way around a silicon junction voltage reduces at -2mV/degC.
Exactly, as the temperature rises, the voltage drops, so lower temperatures should yield higher a efficiency.

As long as the solar panels aren't covered in snow, the colder it is, the more power you'll get, for the same amount of sun.

What's it like today? Where, I live most of the snow has now melted, although it's still near freezing.
Title: Re: UK solar doldrums
Post by: woody on March 19, 2018, 11:07:01 pm
Over here (Netherlands) today it's completely cloudless with an outside temperature of 3 deg. C. The maximum power I saw today from our 30 panels (one of which is broken) is around 6300W, average inverter temperature is 35 deg C, average panel temperature is 25 deg. C. A total of 7200Wp is installed with (not so efficient) microinverters.

In my experience clear days in spring (March/April/May) always have higher yields than clear days in summer. Monthly yields are higher in summer due to more fair weather and longer days, but record days are always in the spring.

I think this is not only due to lower panel temperatures but also because the air contains much less water on fair cold days. What also helps is the fact that my panels are at angles that work better in spring (45+55 degrees).

Title: Re: UK solar doldrums
Post by: woody on March 20, 2018, 03:45:15 am
And indeed, today's total generation is at an all -time-high of 38.1 kWh. Now I wish I had replaced the one broken microinverter earlier....
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 20, 2018, 05:17:13 am
Wowww thats amazing around 7.2Kwh per Kw installed!!
I made 2.8Kwh per Kw installed today a record for this year so far :)
Mine is lower partly because I dont export so everything is used in the house.
Peak power today was 0.9Kw per Kw, this depends on the load offered at the best time of day, it sometimes hits 1.05Kw.
I agree on spring sunshine, again my panels are about 52degrees that also happens to be my Lattitude :)
Clearer air, no high haze this time of year and no airborn dust from the feilds, as for pollution the surrounding pig farms dont seem to affect solar as much as my nose hahaha
About the same conditions here Hero :) and yes the Axitec panels Pmpp increases 0.45% every degree C lower.
Title: Re: UK solar doldrums
Post by: woody on March 20, 2018, 07:14:39 pm
I'm not sure how you arrive at 7.2kWh/kW installed. PVOutput tells me 5.3kWh/kW which seems more accurate. Still amazing to me; our yearly average hovers around 2kWh/kW  ;D
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 20, 2018, 08:47:50 pm
I'm not sure how you arrive at 7.2kWh/kW installed. PVOutput tells me 5.3kWh/kW which seems more accurate. Still amazing to me; our yearly average hovers around 2kWh/kW  ;D
Neither am I and I cannot now figure out how I arrived at such a number, many thanks for the correction :)
My annual average is just about 1.1Kwh/Kw but that includes downtime for tinkering, holidays when it's switched off and as explained earlier the fact that I don't export. Your figures show me what is possible, may I ask your lattitude and oriantation ? Mine is 52,35N and SSW(235deg) almost on the meridian, roof angle 51deg.
Title: Re: UK solar doldrums
Post by: woody on March 21, 2018, 02:13:59 am
Our position is 52.44N 4.40E, give or take a couple of miles. Orientation is 190 deg. 16 panels under 55 deg and 14 panels under 45 deg. We have lots of part-time shading, hence the micro inverters. The system is net connected and always on. Except the one inverter that broke down last March and still is not fixed by me :-[
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 21, 2018, 03:28:01 am
Were almost identical, very interesting to exchange information, fortunatly I dont have any serious shading. I have wondered about a steerable array to pick up the rising sun but from what I could estimate the power gain would not justify it. Interesting issue with micro inverters having to scamper up the roof to replace them but as you say good for heavy shading.
Title: Re: UK solar doldrums
Post by: woody on March 21, 2018, 04:16:48 am
Are you east or west in the UK?

Microinverters are a bit of a tradeoff imo. Using them means (apart from a number of other advantages) that if one stops, the rest of the system keeps working. When your central inverter fails, nothing works. The downside is indeed that for every failing inverter you have to go on the roof, remove the panel, replace the inverter underneath and reinstall the panel. Which is a b*tch. So it gets postponed as long as possible.

I use Enecsys inverters.These inverters were sold with an operating life expectancy of greater than 25 years and came with a 25 year warranty. They were designed to be more or less unbreakable due to not using electrolytic caps inside.  I got them in early 2013 and then Enecsys became insolvent in early 2015. So much for the warranty. Out of the 30 inverters on my roof I have 2 broken so far. I'm kinda hoping that these 2 are the early failures on the left side of the bathtub curve  :)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 21, 2018, 08:23:53 pm
East 0,48E in East Anglia so quite close to the Netherlands :)

As for microverters IMOP the cost is very hard to justify dramatically increasing the payback time of the system but for many that is not a concern. Also for me I wanted to build my own converters for water heating so microverters were not an option. I have see many blown single inverters on Ebay and many lurid stories about failures so I guess the commercial units are built for a price. I had a few mosfet failures in the early day's caused by turning on the immersion heater switch with inadiquate gate voltage but since then no more problems.

Shame about Enecsys they had a good idea but I guess the real world performance was not up to the marketing hype hence the companies failure.

Beutiful sunny day here today so out potato planting :)
Title: Re: UK solar doldrums
Post by: woody on March 21, 2018, 09:36:10 pm
We indeed are at comparable latitudes. Nice for comparison.

I'm still not decided about those micro inverters. They do solve the 'bad panel in a string', mppt-per-panel and shading problem. The latter is important on my roof. Single point of failure vs multi point of failure is also better with micro inverters. But IF something goes wrong there is way more work than with a single inverter. I start to see that as a disadvantage. Then there is the better monitoring, you can pinpoint malfunctioning solar panels. But solar panels themselves hardly ever fail so that advantage is minimal. A last advantage is that you don't have high DC voltages on the roof. Only 230VAC. Disadvantages are slightly higher costs and slightly lower efficiency.

If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.

Title: Re: UK solar doldrums
Post by: coppice on March 21, 2018, 10:32:01 pm
Are you east or west in the UK?

Microinverters are a bit of a tradeoff imo. Using them means (apart from a number of other advantages) that if one stops, the rest of the system keeps working. When your central inverter fails, nothing works. The downside is indeed that for every failing inverter you have to go on the roof, remove the panel, replace the inverter underneath and reinstall the panel. Which is a b*tch. So it gets postponed as long as possible.

I use Enecsys inverters.These inverters were sold with an operating life expectancy of greater than 25 years and came with a 25 year warranty. They were designed to be more or less unbreakable due to not using electrolytic caps inside.  I got them in early 2013 and then Enecsys became insolvent in early 2015. So much for the warranty. Out of the 30 inverters on my roof I have 2 broken so far. I'm kinda hoping that these 2 are the early failures on the left side of the bathtub curve  :)
If a small company offers you a 25 year warranty, you can be sure they aren't expecting to be around for long, and probably don't care too much about the product's durability. Even if its a big company, they may have partitioned the activity into a subsidiary which they can let go to the wall, without pulling down the main enterprise.

Micro-inverters seem to be very popular in the US. They nicely avoid things like shade issues, but the cost is a problem.
Title: Re: UK solar doldrums
Post by: ahbushnell on March 22, 2018, 01:18:33 am
We indeed are at comparable latitudes. Nice for comparison.

I'm still not decided about those micro inverters. They do solve the 'bad panel in a string', mppt-per-panel and shading problem. The latter is important on my roof. Single point of failure vs multi point of failure is also better with micro inverters. But IF something goes wrong there is way more work than with a single inverter. I start to see that as a disadvantage. Then there is the better monitoring, you can pinpoint malfunctioning solar panels. But solar panels themselves hardly ever fail so that advantage is minimal. A last advantage is that you don't have high DC voltages on the roof. Only 230VAC. Disadvantages are slightly higher costs and slightly lower efficiency.

If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.
Isn't the reduced efficiency offset by fixing the shading problem?
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 22, 2018, 03:11:19 am
If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.
I have seen central inverters with 2 seperate mppt channels supporting 2 strings and hence reducing the voltage and helping with shading. I would not be suprised if a little hunting might turn up one with even more though that doesnt help your single point of failure issue. Another thing that concerns me with many recent inverters is they are so called "transformerless" for a gain of a few percent efficiency (read reduced manufacturing cost) and IMOP dramatically reduced safety by connecting your rooftop panels directly to the grid!
Title: Re: UK solar doldrums
Post by: capt bullshot on March 22, 2018, 05:28:15 pm
If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.
I have seen central inverters with 2 seperate mppt channels supporting 2 strings and hence reducing the voltage and helping with shading. I would not be suprised if a little hunting might turn up one with even more though that doesnt help your single point of failure issue. Another thing that concerns me with many recent inverters is they are so called "transformerless" for a gain of a few percent efficiency (read reduced manufacturing cost) and IMOP dramatically reduced safety by connecting your rooftop panels directly to the grid!
The rather high DC voltage with these (typically 300V under full load, but allowed to 450V for smaller ones, and 900V for large installations) is way more dangerous than the direct mains connection. In case of a broken wire within the panels or the wiring, you'll get a nice arc setting your roof on fire (yes, the panel's plastic rear side can burn like hell). And there's another issue with the non-symmetric DC volatage in relation to earth with some panel, causing early degradation by some weird kind of internal material migration.
Anyway, mine (a dual string transformerless one) does just fine, and I haven't seen any dead pigeon dropping from my roof yet ;)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 23, 2018, 01:07:42 am
If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.
I have seen central inverters with 2 seperate mppt channels supporting 2 strings and hence reducing the voltage and helping with shading. I would not be suprised if a little hunting might turn up one with even more though that doesnt help your single point of failure issue. Another thing that concerns me with many recent inverters is they are so called "transformerless" for a gain of a few percent efficiency (read reduced manufacturing cost) and IMOP dramatically reduced safety by connecting your rooftop panels directly to the grid!
The rather high DC voltage with these (typically 300V under full load, but allowed to 450V for smaller ones, and 900V for large installations) is way more dangerous than the direct mains connection. In case of a broken wire within the panels or the wiring, you'll get a nice arc setting your roof on fire (yes, the panel's plastic rear side can burn like hell). And there's another issue with the non-symmetric DC volatage in relation to earth with some panel, causing early degradation by some weird kind of internal material migration.
Anyway, mine (a dual string transformerless one) does just fine, and I haven't seen any dead pigeon dropping from my roof yet ;)
Not that I wish to provoke an argument on our thread devoted to output but the operating conditions of the panel string is identical irrespective of whether there is a transformer in the inverter or not, the only differance being whether or not they are galvanically isolated from the grid, so all of your worries concerning arcs etc apply equally to a transformerless inverter regardless of what you may have been told by your installer.
Title: Re: UK solar doldrums
Post by: Monkeh on March 23, 2018, 01:13:29 am
If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.
I have seen central inverters with 2 seperate mppt channels supporting 2 strings and hence reducing the voltage and helping with shading. I would not be suprised if a little hunting might turn up one with even more though that doesnt help your single point of failure issue. Another thing that concerns me with many recent inverters is they are so called "transformerless" for a gain of a few percent efficiency (read reduced manufacturing cost) and IMOP dramatically reduced safety by connecting your rooftop panels directly to the grid!

Forget to turn off the DC isolator and you can get a pretty nasty surprise - it's not directly connected but I've had a ~600V leakage belt out of mine, that woke me up in a hurry. The big isolators and labels aren't for show!
Title: Re: UK solar doldrums
Post by: woody on March 23, 2018, 02:51:50 am
Isn't the reduced efficiency offset by fixing the shading problem?

On my roof I'm pretty sure that that's the case. The reduced efficiency is only a couple of percent anyway and I am not really complaining. Only noting that on bright days in summer when shading is less of an issue some electricity is wasted by micro inverters when compared to central inverters.

To be honest, I think it is really difficult to prove one system is better than the next. Way too many variables are at play.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 23, 2018, 05:24:03 am
Isn't the reduced efficiency offset by fixing the shading problem?

On my roof I'm pretty sure that that's the case. The reduced efficiency is only a couple of percent anyway and I am not really complaining. Only noting that on bright days in summer when shading is less of an issue some electricity is wasted by micro inverters when compared to central inverters.

To be honest, I think it is really difficult to prove one system is better than the next. Way too many variables are at play.
Exactly :) a few percent here or there can easely be lost in measurement accuracy, I think the choice is personal maybe even depending on availability of something for a good deal at the time. Most people will stand by what they have selected and thats only natural :) Sadly the clouds from the Atlantic arrived this afternoon, westerlies bad for solar, easterlies bad for potatoes what a choice :)
Title: Re: UK solar doldrums
Post by: woody on March 23, 2018, 06:40:27 pm
And not only measurement accuracy. Bird shit. Leaves. Lichen. Temperature. Snow. Clouding. Humidity. Con trails. Fired ground fault interrupters that only get noticed after a week. There are a myriad of reasons why a solar array does not deliver its designed output. The choice of inverter technology is only one of them and in my experience, a small one at that.

Hope the potatoes work out or else it's going to be a lot of Fish and Chips in the fall  :D
Title: Re: UK solar doldrums
Post by: Bassman59 on March 24, 2018, 11:18:00 am
I live in sunny Tucson, Arizona. There are 18 panels on my roof, with a maximum generation capability of 6.1 kW. The energy production is about 40 kWh a day, and right now most of that is going back to the grid. We don't turn the air conditioning on until the monsoon season (July) when the humidity makes swamp cooling ineffective. Even with the A/C on in the summer, I expect to have electric utility bills that are just the connection fees and the taxes, around $22/month.

We expect mid-summer daytime temperatures to be above 100ºF starting in May, and it'll remain like that until the end of September.  If this year is like last year, we'll have a month of 110ºF + days in the middle. Wheeeee!
Title: Re: UK solar doldrums
Post by: paulca on March 26, 2018, 06:04:46 am
Well my nano setup hit boost voltage on the battery for the first time.  Panel voltage shot up, amps fell, battery pinned at 14.40V, so rapidly found things to charge off it.  I now have a pile of charged LiPos.  No point wasting sunlight.  I expect I'll be needing it next few days look rubbish and it can be cloudy for weeks at a time here, so having an energy stock pile helps.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 26, 2018, 08:40:09 pm
I live in sunny Tucson, Arizona. There are 18 panels on my roof, with a maximum generation capability of 6.1 kW. The energy production is about 40 kWh a day, and right now most of that is going back to the grid. We don't turn the air conditioning on until the monsoon season (July) when the humidity makes swamp cooling ineffective. Even with the A/C on in the summer, I expect to have electric utility bills that are just the connection fees and the taxes, around $22/month.

We expect mid-summer daytime temperatures to be above 100ºF starting in May, and it'll remain like that until the end of September.  If this year is like last year, we'll have a month of 110ºF + days in the middle. Wheeeee!
A solar power paradise, payback very fast I should imagine where here in northern europe it's a real struggle to make it economic. Many years ago the subsidies were very much higher but I dont see many new installations going in now, ok for those already on high subsidies as I seem to remember they were fixed for 25 years..........
Title: Re: UK solar doldrums
Post by: fourtytwo42 on March 26, 2018, 08:42:34 pm
Well my nano setup hit boost voltage on the battery for the first time.  Panel voltage shot up, amps fell, battery pinned at 14.40V, so rapidly found things to charge off it.  I now have a pile of charged LiPos.  No point wasting sunlight.  I expect I'll be needing it next few days look rubbish and it can be cloudy for weeks at a time here, so having an energy stock pile helps.
Sounds like your ready for anything the atlantic has coming to you, forecast for later this week not to good over here in the east either. So hopefully this will encourage you now we are past the spring equinox the worst part of the year is done with and it's make hay while the sun shines :)
Title: Re: UK solar doldrums
Post by: coppice on March 26, 2018, 09:04:35 pm
I live in sunny Tucson, Arizona.
A solar power paradise, payback very fast I should imagine...
Yeah, but you use a lot of that power just running the air cons.  :)
Title: Re: UK solar doldrums
Post by: paulca on March 26, 2018, 09:19:35 pm
Well my nano setup hit boost voltage on the battery for the first time.  Panel voltage shot up, amps fell, battery pinned at 14.40V, so rapidly found things to charge off it.  I now have a pile of charged LiPos.  No point wasting sunlight.  I expect I'll be needing it next few days look rubbish and it can be cloudy for weeks at a time here, so having an energy stock pile helps.
Sounds like your ready for anything the atlantic has coming to you, forecast for later this week not to good over here in the east either. So hopefully this will encourage you now we are past the spring equinox the worst part of the year is done with and it's make hay while the sun shines :)

If only lead acids weren't so expensive.  I would consider doubling up on the 26Ah.  Instead I can charge all my RC LiPos and use them until the sun returns :)

Downside is, they don't like being fully charged, so they need to be used up first.
Title: Re: UK solar doldrums
Post by: woody on March 27, 2018, 06:12:17 pm
payback very fast I should imagine where here in northern europe it's a real struggle to make it economic. Many years ago the subsidies were very much higher but I dont see many new installations going in now, ok for those already on high subsidies as I seem to remember they were fixed for 25 years..........

Yes, but many years ago solar panels were much more expensive and much lower in power.

I'm not too pessimistic about this. I think that you can run solar on your rooftop without subsidy and at least break even.

The biggest problem IMO (at least here in Holland) is that solar was and is sold to people as a moneymaker. The installation cowboys promise a 7-10% ROI on your system. So much more than your bank gets you on your savings account. Only, that kind of ROI is all coming from subsidies.

The honest story should be that solar is a means to make all the electrical power you need in the cleanest way possible. Somewhere in the near future you will be paying a decent fee to solve the problems you create because you make way too much in summer and make way too little in winter (so somewhere somehow some storage or alternative generation has always to be on stand-by for you). You will be paying your energy tax like everybody else. But still you will break even in the time your installation runs (20 years). So the ROI moneywise (if there at all) is low but the ROI for the environment is high.

Subsidies should be used to get new technology out of the lab and into the field. But when new technology can hold its own they should vanish pronto. We have a gigantic problem on our hands that will cost us many many billions to solve. There are better ways to spend that money than subsidizing already proven technology.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 12, 2018, 06:16:57 pm
Third sucsesive day of fog here and that was preceded by several days of rain so the daily output has been at winter levels for a week now, only saving grace is the extended hours of very low output! Apparently the scientists say the gulf stream is weekened by ice melt (global warning) hence our stuck claggy weather systems so maybe the clock is ticking against solar in northern europe. Maybe that retirement cottage/tent in the Sahara beckons  :-DD
Title: Re: UK solar doldrums
Post by: paulca on April 12, 2018, 06:22:46 pm
Yea, looks like the whole of April is set to be cool, wet and breezy.  Nothing unusual over here though.  Fingers crossed for May.
Title: Re: UK solar doldrums
Post by: woody on April 12, 2018, 07:10:27 pm
Today is grey. Yesterday was good. The whole of April so far looks nothing like last year; I need to make 500kWh in the 18 days left to equal it. And looking at the forecasts that's not gonna happen. Good thing is it will help me explain to my wife why I decided to cut down on the vacuuming :-)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 12, 2018, 08:10:26 pm
Good thing is it will help me explain to my wife why I decided to cut down on the vacuuming :-)
Carefull she might suggest you buy a vintage hand powered one!
Actually in our house the oil boiler and heating pump combined use about a unit a day in cold weather and thats from 25-30% of our entire consumption! Roasting a joint uses about 3 units but hell I just love roast dinner :)
Title: Re: UK solar doldrums
Post by: woody on April 17, 2018, 03:15:30 am
Today was a good day: 38.1 kWh. Forecasts promise lots of sunshine up until Saturday .  8)

That boiler uses little energy then. Our (natural gas) CV from 2011 uses at least 2 kWh per day in cold weather. On a yearly basis this turns out to be one of the most energy consuming devices in our house. The oven with the occasional steak and Guinness stew does not come close, that's for sure.

But, as I make more power in a year than I need, I don't complain.
Title: Re: UK solar doldrums
Post by: metrologist on April 17, 2018, 11:46:04 pm
Jeebs my average household energy use barely cracks 10kWHr
Title: Re: UK solar doldrums
Post by: paulca on April 18, 2018, 12:00:28 am
Jeebs my average household energy use barely cracks 10kWHr

Per?
Title: Re: UK solar doldrums
Post by: metrologist on April 18, 2018, 12:50:05 am
 :palm: daily use
Title: Re: UK solar doldrums
Post by: paulca on April 18, 2018, 12:55:15 am
Yea, mines about the same.  10-15kWh/day.  Circa £1.50-£2 per day.  £50 of leccy lasts me about a month.  Less in summer as less lights, less heating running (gas boiler still and pump uses about 300W).

Changed all my bulbs to LED and a few CFLs, so the main consumers now would be:

1) The PC/Monitor, 150W idle, 450W gaming.
2) Cooker/microwave
3) The incandescent 300W up-lighter (though usually dimmer to about 25%) to light the main living space, although I intend to see how well an LED replacement does.

When I move house the plan is to install enough solar and batteries to run the PC from solar.
Title: Re: UK solar doldrums
Post by: metrologist on April 18, 2018, 02:04:59 am
I always blame the fridge. My "gaming" PC is about 5 years old and draws 100W surfing (I've lost my lust for games). I should just get a netbook or something more economical for that. We use mostly gas for cooking, and I don't usually run the heat or AC. Gas is actually costing a good portion of the bill now - that is just hot water and the stove. ~$70USD/mo total and we are billed in two tiers, $0.20 and $0.28/kWh.

I have a couple of white gas camping stoves that I should try using for a month to see, and soon I'll turn down the water heater. I miss the $40 bills.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 18, 2018, 02:54:45 am
That boiler uses little energy then. Our (natural gas) CV from 2011 uses at least 2 kWh per day in cold weather. On a yearly basis this turns out to be one of the most energy consuming devices in our house. The oven with the occasional steak and Guinness stew does not come close, that's for sure.
I supliment the boiler with a woodstove in the lounge afternoons and evenings in winter so the boiler is only used in the mornings, usually an hour, sometimes two if its extremely cold. Like you said before it's all about insulation, all the windows are argon filled, the walls are filled with foam and the roof with up to 500mm of fiberglass.

I am shocked by other peoples daily electric consumption here, ours is 3.5Kwh/day on average and that includes an electric cooker BUT if we use the oven (an exception) it's a 6Kwh day! We also rarely watch television (boring) a DVD is probably half a unit :) We do lots of small things to save energy for example using a big thermos to store boiled water to save boiling the kettle to make tea all the time, using simple laptops and having all non-essentials not on standby but unplugged. We have a small modern chest freezer that is only on for 6 months (summer harvest surpluss) and a well insulated modern fridge freezer. All lighting is CFL and I try to only run irrigation pumps when the sun is out and of course in summer a lot of our cooking is outdoors :) Our background power is about 45W but I am always working to reduce it, thats where I keep thinking of installing a DC-bus, so many gadgets many with small mains transformers with 1W magnetisation current, but they get swamped by the fridge etc anyway :( ho hum!
Title: Re: UK solar doldrums
Post by: woody on April 18, 2018, 06:41:06 am
@fourtytwo42
I admire your efforts!

We use approx. 5300kWh / year, or a bit less than 15 kWh / day. We run a house, an office with a couple of computers and a server and my workshop on it. So all in all not too bad taking into account that all the living and the making of money is done here and no office buildings elsewhere need to be kept warm and lighted for us. My other excuse is that the solar panels on the roof generate 5400+ kWh / year so in principle all electricity we use is home-made, green and already paid-for and we do not have to be frugal with it.

But (and this is a big but) this only works because of the so-called 'salderingsregeling' in my country, which means that generated (and grid-delivered) kWh's cancel out kWh's we take from the grid 1:1. Which is quite unreasonable as in the summer during the day we generate a lot of energy that maybe nobody uses, while at night and in the winter a big, probably coal fired power station somewhere is making the energy we use then. For that luxury we do not pay a cent.

Good thing that this salderingsregeling will be moderated in a couple of years. This will be an incentive to save power. I only hope they'll invest the money I then give them in storage. Although more tarmac is more likely  :(

@metrologist
Early 2016 I replaced the desktop (120W) with an Intel NUC. As long as you do not try to render Avatar on it it works perfectly. It runs webbrowsers, LibreOffice, Lightroom, Kicad, Eagle, Gimp etc. with 'twee vingers in z'n neus', as we say. And that while using <15W. Also replacing the 10 year old CCFL based monitor with an LED unit saved nearly 50 watts.

And I would trade you our gas bill anytime. We use approx. 2500m3/year, at €0.57/m3. For heating the house, the office and the workshop (85%)  and hot water for showers etc (15%).
Title: Re: UK solar doldrums
Post by: paulca on April 18, 2018, 09:08:52 pm
I always blame the fridge. My "gaming" PC is about 5 years old and draws 100W surfing

5 years you might be okay, but around that time the PC hardware folks came under serious scrutiny about power usage of devices.

I was spec'ing a gaming system back then that needed a 650W power supply.  The next system, 3 years ago I was worried I'd be looking at 1000W PSU, but... as it turns out the new one consumed less.

It's the video card that churns through the power when running flat out.  I believe mine consumes something like 200W at full tilt, the CPU up to 220W.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 19, 2018, 05:05:52 am
1st BBQ of the year and a record production for 2018 so far of 3.4Kwh/KW of our quirky PV installation. The oil boiler has not been on for several days and we have more hot water than we know what to do with (we don't wash much  :-DD). Of course if we were exporting to the grid like most I know our production would be much higher but this is an entirely subsidy free system :)

In connection with the other day and consumption figures we do use extra power in winter as we run a de-humidifier, this contributes some heat as well as enabling us to keep the windows tight shut in all the nasty cold weather. I found the humidistat in modern de-humidifiers totally useless, the old one that was near on 30 years old before the coolent circuit was perforated beyond repair ran a hair humidistat and worked perfectly. The new de-humidifier is overridden by yet another of my gadgets enabling the energy consumption to be sensibly controlled.

@woody

Thats a good combination of premises use and of course also avoids commuting! There is just two of us and I am retired although still run some consultancy also home based. I reckon the amount of hardware/software I get involved in now has hardly diminished as now I don't have to waste valuable time politicing and stuck in endeless meetings  :-DD  On top of that we grow our own fruit & veg and I am an avid home brewer hick!!
Title: Re: UK solar doldrums
Post by: NiHaoMike on April 19, 2018, 11:32:04 am
I always blame the fridge. My "gaming" PC is about 5 years old and draws 100W surfing

5 years you might be okay, but around that time the PC hardware folks came under serious scrutiny about power usage of devices.

I was spec'ing a gaming system back then that needed a 650W power supply.  The next system, 3 years ago I was worried I'd be looking at 1000W PSU, but... as it turns out the new one consumed less.

It's the video card that churns through the power when running flat out.  I believe mine consumes something like 200W at full tilt, the CPU up to 220W.
Sandy Bridge was the last time the performance per watt jumped by a large amount. After that, the improvements were more or less incremental. I have an old HP Z600 (Westmere - just one generation older than Sandy Bridge) that I rarely use because it is not particularly efficient. (And running it as a miner really heats up the room - handy on very cold days but not profitable otherwise.)

GPUs use a lot of power, but the performance per watt is still improving a lot with every generation at this point.
Title: Re: UK solar doldrums
Post by: paulca on April 19, 2018, 04:44:22 pm
Monitors and TVs have become much more efficient too.  I have two monitors here.  Both Acer.  A 24" 16:9 and a 34" 21:9 1440p.  Guess which consumes more power?  The smaller one as it's about 4 years older.  When it's been on for a while it's about 50*C at the top vent.  The larger, newer monitor even runs off a DC brick and is barely more than ambient at it's exhaust vent.
Title: Re: UK solar doldrums
Post by: NiHaoMike on April 19, 2018, 05:13:16 pm
Monitors and TVs have become much more efficient too.  I have two monitors here.  Both Acer.  A 24" 16:9 and a 34" 21:9 1440p.  Guess which consumes more power?  The smaller one as it's about 4 years older.  When it's been on for a while it's about 50*C at the top vent.  The larger, newer monitor even runs off a DC brick and is barely more than ambient at it's exhaust vent.
My Seiki 50" 4K only uses about 40W. Of course, it really is more of a monitor than a TV with very limited ability to play media by itself. Basic upscaling can use surprisingly little power, however - a Tegra X1 can upscale 1080p to 4K on just 6W. A desktop GPU will easily outdo it in upscaling quality, though. (I have to admit that I have no idea how much power my 970 uses just doing 1080p to 4K upscaling since I started mining Curecoin/Foldingcoin well before I found content that really does call for good upscaling.)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 20, 2018, 05:40:09 am
Monitors and TVs have become much more efficient too.  I have two monitors here.  Both Acer.  A 24" 16:9 and a 34" 21:9 1440p.  Guess which consumes more power?  The smaller one as it's about 4 years older.  When it's been on for a while it's about 50*C at the top vent.  The larger, newer monitor even runs off a DC brick and is barely more than ambient at it's exhaust vent.
My Seiki 50" 4K only uses about 40W. Of course, it really is more of a monitor than a TV with very limited ability to play media by itself. Basic upscaling can use surprisingly little power, however - a Tegra X1 can upscale 1080p to 4K on just 6W. A desktop GPU will easily outdo it in upscaling quality, though. (I have to admit that I have no idea how much power my 970 uses just doing 1080p to 4K upscaling since I started mining Curecoin/Foldingcoin well before I found content that really does call for good upscaling.)
Hey guy's thanks for the info I didnt realise LED display's saved so much compared with CCFL's, of course all my displays are the latter. I kinda know how much computing efficiency has moved on from the bad old P4 days :) I run a smallish T2300 laptop on about 75W and just put up with the extra time simulations and compilations take (time for more tea :)) I am always looking for way's to save energy as well as generate it, one of my biggest standing consumers is the DSL modem, 15W 24/7 :( turn it off and the exchange software marks you down, it doesnt understand your just trying to save energy!

P.S. Another cracking 3.3Kwh/Kw production today but there are clouds on the horizon!
Title: Re: UK solar doldrums
Post by: coppice on April 20, 2018, 05:45:06 am
Hey guy's thanks for the info I didnt realise LED display's saved so much compared with CCFL's.
LED backlighting does save quite a lot of power in a modern LCD monitor, but you shouldn't discount how much the power draw of every other component has dropped. The use of finer geometries and higher integration levels has transformed the chip sets from rather hot to barely warm.
Title: Re: UK solar doldrums
Post by: paulca on April 20, 2018, 05:16:43 pm
That and voltage.  The CPU/GPU race has been about running on lower and lower core voltages to save power.  Higher voltage usually means more heat.  Overclockers will generally up the voltage as it allows for faster clock speeds without lock ups, with caveats about burning it out, though they are fairly well protected.

Today things like the i7 and (I believe) Ryzen have variable voltage, so when idle the drop their voltage to a minimum and consume less power, produce less heat, but when you kick off a compilation or a game the voltage ramps up, along with the clock frequency/divider.

I believe they are as low as 1.1v in some cases, maybe lower.  My CPU is power hungry and runs at 1.45V :(
Title: Re: UK solar doldrums
Post by: woody on April 21, 2018, 03:48:12 am
As a panel owner you got to love the spring: another 38.8 kWh  (5.3 kWh / kW) day  8) I just GOT to replace that inverter to get this to 40k...
Title: Re: UK solar doldrums
Post by: fourtytwo42 on April 21, 2018, 04:58:09 am
As a panel owner you got to love the spring: another 38.8 kWh  (5.3 kWh / kW) day  8) I just GOT to replace that inverter to get this to 40k...
Good weather for being on the roof too, no nasty slippy slidy wet moss!! SWMBO is really keen on this this year, she checks if the grid tie is running before doing the ironing  ;D
Title: Re: UK solar doldrums
Post by: woody on May 01, 2018, 07:55:45 pm
Spring 2018 in NL. Yesterday I made 0.879 kWh. In a day. With 7kWP on the roof. The day before that 1.05 kWh. The entire month of April was 86kWh behind April 2017.

On the up side, the rain just stopped, the sun shines a bit and forecasts for the next week are not bad. And the boat floats again after spending the winter on the shore  8)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on May 02, 2018, 02:53:15 am
Just plotted mine till the end of April, spring came, the plums and damsons all flowered and immediatly we were hit by a cold washout! 1C last night :( Apples are just starting now so I hope the weather improves for the bees in time!

Y axis is weekly average Kwh/day, X axis is hours.

House was in danger of floating away a while ago, who needs a boat  :-DD
Title: Re: UK solar doldrums
Post by: G7PSK on May 02, 2018, 06:27:35 pm
I am looking at getting solar, but I think wind might be better here in Norfolk so am looking at that as well. I built a wind system for my father twenty years ago and although he no longer is there last time I went past the turbine was still up.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on May 02, 2018, 09:05:15 pm
I am looking at getting solar, but I think wind might be better here in Norfolk so am looking at that as well. I built a wind system for my father twenty years ago and although he no longer is there last time I went past the turbine was still up.
I live in Norfolk too :) I have also tried wind but if you only have a small plot it's very very fussy and the planning regs get in the way hence I gave that up and moved to solar. There are still problems with the planning regs (not enough room to fit tracking gear on a roof) but I am getting a lot more output than I ever managed from wind. Depends entirely upon your circumstances and I guess you already know about the problems with turbulent flow and obstacles to close!
Title: Re: UK solar doldrums
Post by: woody on May 04, 2018, 03:34:58 am
I just GOT to replace that inverter to get this to 40k...

Scratch that. Today, not too hot and very very sunny, we made 40.920 kWh / 5683kWh/kW. That is an all time high for this installation.  8)
Title: Re: UK solar doldrums
Post by: paulca on May 04, 2018, 05:29:25 pm
My mini 50W system has been running with full battery now for a week.  With a few blue sky days I got all my batteries charged and the broken sunshine since is just enough to keep up with demand of my phone, electronics PSU and USB devices.

I bought a 22400mAh power bank to try and capture some more of the energy for when it becomes miserable and dark again.  So that came at 70% charge so didn't really dent the solar battery that much charging it. 13.1V down to 12.6V.  Today will probably put that back to 13V

If only it was this easy in winter.

Title: Re: UK solar doldrums
Post by: woody on May 24, 2018, 04:49:22 pm
Got the yearly settlement from my power company yesterday. Used 3753 kWh from the grid and put back in 4193 kWh. That leaves me with 440 kWh * €0,11 * 1.21 (VAT) = €58,56 in cash.

Total electricity use over the last year (including the energy generated by the panels and directly used) was 5367 kWh. Up 1.9% from the year before. Which fuels my pet peeve that LED lamps do not save energy  >:D

Oh, and May 2018 is looking to be a very good month for solar over here  8)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on May 25, 2018, 03:19:04 am
Woww Woody good figures indeed :) So adding your saved electric bill to your rebate have you worked out how many years the system will take to break even on present performance ?

Last week was great here averaging over 3Kwh/day/Kw but as usual I lost quite a bit through not having completely converted the household to not using electricity unless the sun is shining and the water is hot already  ;D

IMOP the CCFL's are/were far more efficient till someone discovered they had a drop of mercury in them and outlawed them, I wonder what poison they will decide exists in LEDs meaning the get the same treatment in years to come!!
Title: Re: UK solar doldrums
Post by: metrologist on May 25, 2018, 03:38:48 am
I've been very happy with all my LED lights, and the W numbers printed in them are much lower than the CCFL's they replaced.

In two rooms, however, there are remote 4-pin CCFL supplies where I used compatible LED bulbs - so I am sure some efficiency is lost.

My lowly panel just keeps my battery topped up. It would be much better if I set up my aquariums to run off solar, and just during sun time too. That's only 12W.  :-\
Title: Re: UK solar doldrums
Post by: woody on May 25, 2018, 05:52:56 pm
So adding your saved electric bill to your rebate have you worked out how many years the system will take to break even on present performance?
I find that a very difficult discussion. If you look at it from the sunny side break even is maybe 7 years. But I could argue for 15 years as well. It is the same with my car; I never managed to work out the break-even for that.

My take is that since 2013 we produced 25,8MWh of clean energy and thereby avoided between 5 and 12 tons of CO2 (depending on the fuel mix used in the power plant). That at a cost that is cheaper than getting it out of the grid. How much cheaper? I don't know. Time will tell. But cheaper, that is for sure.

And when I take into account the foot-between-the-door effect that decentralized solar systems like mine have on how the grid is run by those big power companies, for me break even is already reached  ;D
Title: Re: UK solar doldrums
Post by: fourtytwo42 on May 26, 2018, 12:32:37 am
Since asking the question I have tried to calculate mine, given its upgrading, early failures and weather changes from year to year it's hard to grab the figures as most of the output is converted into oil fuel savings. My initial small 500W system would have had an estimated payback of 6 years but that was before the oil price shot up recently. The extended 1kw system with a gti but no subsidy has a calculated payback of 4 years, this is in part due to the rising oil price but also because the incremental cost of extending a system is not as high as the initial. My costs are much reduced as a lot of the electronics came from my junkbox (recycling at it's best), the only things directly purchased were the panels themselves and there mounting hardware.

I am also concerned for the environment and this is one way I can contribute, in my case directly by burning less oil for heating :) The contribution via the gti to reduced grid consumption is minimal as unless it's a hot day in summer water heating takes most if not all of the available energy.

I will continue to monitor the results to see if a further extension is worthwile but presently it is large enough to provide all the summer hot water so a larger system would simply spend more time idle! Of course the real nut to crack is energy in the winter, already tried wind and that was no good, I have a small stream but no fall (3 inches on my land at most) and hydro has it's own problems in winter (freezing) leaving heat pumps. I was fortunate enough to experience air source HP's at someone else's expense and they were completely hopeless in freezing weather (spent all there time going into reverse to de-ice the external unit). My trusty woodburner helps out but they are now under threat from PC! I still say the best solution is for mankind to copy the sensible part of the animal kingdom and hibernate for the duration  :-DD
Title: Re: UK solar doldrums
Post by: fourtytwo42 on June 01, 2018, 01:48:54 am
End of this month weekly averages, definetly getting out of the doldrums :) Vertical scale is Kwh/day horizontal is hours so the droop in the middle is Dec/Jan/Feb
Title: Re: UK solar doldrums
Post by: woody on June 01, 2018, 11:07:08 pm
Nice figures!

For our panels it turns out that May 2018 was the best ever; May always is the top month of the year. The previous record was May 2015 with 761 kWh. May 2018 broke that easily: 905 kWh. +19%, with one inverter still broken.

Now what am I going to do with all that power  :-//
Title: Re: UK solar doldrums
Post by: ahbushnell on June 23, 2018, 10:30:57 pm
Updates on energy generation?
Title: Re: UK solar doldrums
Post by: paulca on July 08, 2018, 07:53:38 pm
Updates on energy generation?

It's been unseasonally sunny here in Northern Ireland.  We are into our third or forth week of actual summer weather.  25*C+ blue skies all day.

My 50W panel, in a window has been generating much more than my original demands, so I have taken to charging large LiPos and using them via a laptop car charger to run my laptop in the evenings.

I expect those with large systems will be doing rather well in the UK this last month.
Title: Re: UK solar doldrums
Post by: Bassman59 on July 16, 2018, 01:26:41 pm
I live in sunny Tucson, Arizona.
A solar power paradise, payback very fast I should imagine...
Yeah, but you use a lot of that power just running the air cons.  :)
Like I said, we were running the swamp cooler through May. (OK, I realize that the whole concept of an evaporative cooler makes no sense in the UK.) We turned it on in late May because, well, why not, it was hot.

We were sending back to the grid between 400 and 500 kWh for the months up to May. For the May bill we sent back 216 kWh. The bill ending June 25 we used 422 kWh in excess of what we generated; that is, that month was the first month since the panels were installed (started up beginning of last September) that our use exceeded our generation. We used about the same amount of power this June as last June, about 1600 kWh, which cost almost $250 last year.

Even though May and June are hotter than July (June has many days over 110 degrees F), July is typically the month with the most energy usage here. That's because the humidity becomes unbearably high, as our monsoon season starts. We don't get monsoons in the tropical sense; the native word for the storms is "chubasca," but basically every day starts out hot and dry and as the day progresses, moisture in the air builds up and in the late afternoon we get thunderstorms and a lot of rain, and an hour later both the temperature and the humidity drop significantly. But during the day, before the storms, it's hot and sticky so we run the A/C, and that's our energy use.

Monsoon "season" lasts from July to the middle of September, and its start is defined as when the dew point exceeds 54 degrees F for three consecutive days.

Of course, today it was rainy and the temperature never got above 80 degrees and we opened the windows.

ANYWAY, we have nearly 1300 kWh in credit (what we've generated in excess of what we've used) and my guess is that even with another month of high-ish humidity and temperature, we will end up not paying anything to the utility for our electricity usage.

I really think that in the desert southwest, not having solar panel installations for both residences and businesses is a mistake. The problem is that the incumbent utilities are wholly against residential solar power and probably don't want businesses to have solar power, either.  But rather than invest in solar farms and even installing the panels for customers, they'd rather continue to push the natural-gas-fired turbines as the only source for electricity.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on October 04, 2018, 04:48:11 am
I sooo wish I lived in a hot country and needed aircon, it would be so simple to solar power it per the last post. Interestingly I have spent time near the equator in several countries where aircon is an expensive luxury but PV is almost unheard of. Anyway back to the UK and the doldrums are beginning to return, this is my last 15 months data (rolling averaged over a week) vertical axis in Kwh/day and horizontal in hours so you can see Autumn beginning to have its effect in shorter days and more cloud. The glitch around 9600 hours coincides with downtime caused by equipment experimentation. Ohh I should mention this system is controlled to prevent export so sometimes energy production is limited by what can be consumed locally by water heating or electricity use.
Title: Re: UK solar doldrums
Post by: Kibi on October 10, 2018, 06:49:18 am
Alas, the doldrums are returning rapidly. However, after a recent upgrade of 1.1KW of additional PV atop my garage, my system reached a record of 10.03KWh today here in sunny Norfolk :)
2.78KWh went into the battery, 0.35KWh was used directly. 6.89KWh left the shed and went towards the house, of which 3.4KWh went into my hot water cylinder.
Quite a good day.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on October 11, 2018, 05:03:58 am
Hi Kibi, I knew there was a Norfolk also in the USA but not one in Zimbabwe  :-// So perhaps you have a home in both countries :) Your results are very good, what is the installed power of your solar panels, mine is 4*265W poly ?
BTW according to the weather forecast today was the hottest in October since 2011 BUT tomorrow the rain comes (some say at last!!).
Title: Re: UK solar doldrums
Post by: Kibi on October 11, 2018, 07:47:46 am
Yes, I'm from Zimbabwe, patriotism sometimes gets the better of me when selecting the location settings. No solar doldrums in Zimbabwe, winter time is the best because it is not the rainy season and it's often fine weather for days on end. Alas I don't live there or even visit anymore.
I have a mixture of PV. The modules you buy at any one time are never available the next time you have more pocket money.
Several years ago, I started out with 4x 250W Renesola poly modules followed later on by two Trina Honey 265W poly modules. The latest addition is a set of 4x JA Solar 275W mono modules. A total of 2.63KV nominal. Like a conventional grid tied system, this assortment of PV arrays operates at the maximum power available all day. My system is rather unconventional though. Its mainly Victron components tied together in an ESS system.
1KW Renesola array is DC coupled via a Victron 35A MPPT charge controller. Same for the JA Solar array via its own Victron 35A MPPT controller. These are on a 24V DC system which means they are charging at just about 1KW each at the top end of the charge.
The two Trina modules are in parallel feeding a Enphase Energy M215 micro GTI. This array is over powered for the GTI, but it's fine and only really a waste on sunny days when I have excess anyway. I get about 229 Watts out of the Enphase at full chat. I might get another GTI one day and get more out of those two modules.The Enphase GTI is connected to the AC-OUT of my Victron MultiPlus Inverter / Charger which enables that energy to charge the battery and also to work off grid if necessary. If the grid fails, the MultiPlus will frequency-shift to control the output of the Enphase GTI when the battery is full.
I have configured my MultiPlus with the G83-2 grid code so that it can back feed via its AC-IN when the battery is full and the power has nowhere else to go. Therefore both the DC coupled and AC coupled arrays will go full blast all day without rest. This excess energy then goes back into the house. This is what helps bolster my output figures. I have a Solar iBoost immersion heater controller which ensures that any energy not consumed by house loads goes into the hot water cylinder.
My batttery bank is an old worn out LiFePO4 set that spent the first 8 years of it's life in a motorcycle, where it got hammered, often. The battery bank has a nameplate capacity of about 7KWh, but I'm lucky if I get 4KWh out of it. This is usually enough energy for the electronics lab, workshop and observatory.
The battery's BMS is an OpenReVolt design (from the EV community) but with 4springs firmware instead. This is quite basic and simply signals the MultiPlus with two signals, 1) charging allowed, 2)discharging allowed.
The ESS system is designed to run on Victron's (expensive) CCGX unit which ties the charge controllers, MultiPlus, battery monitors, fuel tanks, GPS (for mobile applications) etc. all together. It performs the data gathering and publishes the data to their (free to use) portal. They have opened up the code (Venus) for the CCGX, so people are running it on RaspberryPi and other machines. I am running Venus on a BeagleBone Black. The portal is still free to use even if you use a RaspberryPi.
It's taken me several years to cobble this lot together, but it's ever so rewarding.
Title: Re: UK solar doldrums
Post by: fourtytwo42 on October 11, 2018, 07:03:14 pm
Good morning Kibi thank you very much for your excellent system description! The problem of mismatched panels can be severe indeed, I was lucky when upgrading from ~500W to ~1Kw to get two more panels of the same make and type. I am sticking at 1Kw for the time being as that is enough to serve the primary purpose of water heating. Unlike just about everybody else as my system was designed from scratch primarily as a water heater it uses a combined buck/boost converter to drive the 3Kw/240Vrms element directly from the panels.  The GTI was added later merely to soak up the excess but is controlled to prevent export. If/when I eventually move house the whole system is up for re-design as I would like to add wind to the mix to provide more winter energy. Your system has the advantage of being able to store excess energy though at 1Kw I really have very little and not enough to amortize the cost of the equipment.
Title: Re: UK solar doldrums
Post by: Kibi on October 11, 2018, 11:51:02 pm
The GTI was added later merely to soak up the excess but is controlled to prevent export.

This is another feature that the ESS system supports. Certain MODBUS energy meters can be included in the system. If one of these energy meters were to be placed directly after your main switch, then any loads downstream of the meter will be supplied by back-fed energy from the MultiPlus. The MultiPlus will do everything it can to ensure that the energy meter reads 0 Watts (or whatever offset you choose). If a 3KVA MultiPlus is runnung at full capacity because a 10KW shower is on, then the remaining 7KW will simply come from the grid.
Of course in the event of a grid failure, the MultiPlus disconnects it's AC-IN, so no loads on that side are supplied.
My dream is to have such an energy meter connected in the Consumer Unit beyond the shower and cooker circuits so that these are never supplied by the system. "Luxury" circuits (ringmains, welders, EV charging) can then sit between the energy meter and MultiPlus' AC-IN to be supplied by Grid Tied renewable energy. Then "critical" circuits like lights, fridge, boiler and security systems can be fed by MultiPlus' AC-OUT and always be supplied by renewable energy until the battery runs down.
I just need to talk to an electrician who understands my needs and is willing to try something different.
Title: Re: UK solar doldrums
Post by: Kibi on October 15, 2018, 04:49:29 am
It's days like today which are really depressing, a start contrast in weather from just a few days ago.

Today my 2.6KW of PV harvested just 300Wh. :( This is one of the worst harvests that I can remember.

This is a snapshot of the pwer levels when the weather was at its most miserable:
(http://www.wkirby.co.uk/Images/Victron/Doldrums.jpg)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on October 15, 2018, 05:46:01 am
Me too, peak today was just 30W and less then 100Wh for the day, means I have to burn expensive oil fuel to heat the water tomorrow morning :( However I must say the garden was in need of a drink and still very dry, maybe a bit more rain tomorrow too. As you can tell as a gardener I am torn hahaha Altogether I collected around 100Ltrs that will be used for all sorts of things including wine & beer making :)
Title: Re: UK solar doldrums
Post by: HB9EVI on October 15, 2018, 05:56:58 am
seems to be quite a grey weather up in the UK, guys

my small 200Wp system fed 500Wh in the batteries today; so far we're just running the house lighting over the system and got along with the capacities of batteries and panels for our needs, but I guess it'll get tight with different weather and the upcoming shorter days.
I'll add soon a 400Wp windmill to back up for the poorer weather days
Title: Re: UK solar doldrums
Post by: nfmax on October 15, 2018, 06:34:48 am
0.28kWh from my 1.7kW panels today. Rain. Lots of rain. Peak 15-minute average power was 170W, at 11:00 to 11:15 BST
Title: Re: UK solar doldrums
Post by: woody on October 17, 2018, 04:20:06 am
22.5 kWh out of our 7.2 kWp system today. On October 16th. This month so far we made 301 kWh. Last year October we made 296 kWh in the entire month.

I know that global warming has little to do with this but whatever the reason 2018 is a GREAT year for solar in NL  8)
Title: Re: UK solar doldrums
Post by: fourtytwo42 on October 19, 2018, 05:07:31 am
22.5 kWh out of our 7.2 kWp system today. On October 16th. This month so far we made 301 kWh. Last year October we made 296 kWh in the entire month.
Great to know your still outperforming me at 3.125Kwh/Kwp in October, best I have seen this month was about 2.4Kwh/Kwp so I reckon your orientation and shading is a mite better than mine and of course the Netherlands maybe has better weather :) But as you say even here October weather is proving weird this year, very very dry still!!
Title: Re: UK solar doldrums
Post by: Kibi on October 20, 2018, 08:45:07 pm
It's been a bit of a rollercoaster week!

Over the last few day at least, the excess energy "has been making a meaningful contribution to the hot water system - which is nice!"

(http://www.wkirby.co.uk/Images/Victron/Solarweek42-18.jpg)