Poll

Do you keep records of your solar production

No I dont have solar
29 (58%)
No I don't care
4 (8%)
I look at the GTI LCD occasionally
5 (10%)
I look at the GTI display often
4 (8%)
I look at the GTI display even after dark
4 (8%)
I have solar, no GTI and I keep records (like Mike)
4 (8%)

Total Members Voted: 49

Author Topic: UK solar doldrums  (Read 23461 times)

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Offline nfmax

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Re: UK solar doldrums
« Reply #250 on: October 14, 2018, 07:34:48 pm »
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
 
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Offline woody

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Re: UK solar doldrums
« Reply #251 on: October 16, 2018, 05:20:06 pm »
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)
 
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Offline fourtytwo42

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Re: UK solar doldrums
« Reply #252 on: October 18, 2018, 06:07:31 pm »
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!!
 

Offline Kibi

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Re: UK solar doldrums
« Reply #253 on: October 20, 2018, 09:45:07 am »
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!"


 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #254 on: October 21, 2018, 08:14:07 pm »
Do you get paid for your export Kibi ?
 

Offline Kibi

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Re: UK solar doldrums
« Reply #255 on: October 24, 2018, 08:56:13 am »
Do you get paid for your export Kibi ?

No, "export" in my current system refers to energy being "exported" beyond my own private meter which is installed in the Consumer Unit for the workshop (an outbuilding). This exported energy ultimately gets consumed within the house. If the house loads are covered, then any excess will be consumed by the immersion heater which is controlled proportionally by a Marlec Solar iBoost.
No energy actually leaves the house into the grid.
One day when I get a "proper" domestic roof installation, I'll have it tied in to this system and ensure that as little energy is wasted into the grid as possible.
 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #256 on: October 30, 2018, 06:43:26 pm »
Maybe we ought to go for a new competition, worst day recorded (a sort of how low can you go):)

Today from my 1Kw array I got less than 100Wh (logger resolution) and a peak instantaneous power of just 41Watts but it was raining most of the day!
« Last Edit: October 30, 2018, 06:52:03 pm by fourtytwo42 »
 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #257 on: November 15, 2018, 12:05:09 pm »
As the sun gets lower and lower the number of hours of meaningful production goes down too and we become more and more aware of whats on the horizon as our panels see it. As can be seen in the attached pics even at 2pm in the afternoon facing SSW I have a tree who's shadow can also be seen on the panels reducing output from ~500W/Kwe to ~150W/Kwe. Finding somewhere to live where there is nothing on the horizon at this angle is probably impossible  ;D
 

Offline ahbushnell

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Re: UK solar doldrums
« Reply #258 on: November 15, 2018, 01:55:28 pm »
~500W/Kwe to ~150W/Kwe
I'm not familiar with the units W/Kwe?  W is watts.  What is Kwe?

Thanks!
 

Offline metrologist

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Re: UK solar doldrums
« Reply #259 on: November 15, 2018, 02:01:57 pm »
Finding somewhere to live where there is nothing on the horizon at this angle is probably impossible  ;D

 
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Offline fourtytwo42

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Re: UK solar doldrums
« Reply #260 on: November 15, 2018, 02:24:32 pm »
~500W/Kwe to ~150W/Kwe
I'm not familiar with the units W/Kwe?  W is watts.  What is Kwe?

Thanks!
I am very sorry I meant Kwp meaning the peak power, or power installed. So to level the playing field I like to quote everything in per kilowatt installed.
 

Offline ahbushnell

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Re: UK solar doldrums
« Reply #261 on: November 15, 2018, 03:53:43 pm »
Thanks!
 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #262 on: November 26, 2018, 09:49:31 am »
Winter in northern Europe is returning! Here are my stats till today.....

I have done a little more work with pre-processing the data (Cygwin) and presentation in GnuPlot.

The horizontal axis is now week numbers BUT it is not precise as there are holes in the log due to power outages (something we get here in the countryside  :-//)

The main difference between last year and this year is the contribution of the GTI soaking up some of the excess after water heating.

This year there was a few days downtime around wk31 and last year there was lots around weeks 23-26 mostly due to mosfet failures and badly performing software (can't get the staff  ::) ).

The log is a micropower standalone system with a bytewide 32Kbyte EEPROM for storage, two bytes (power & temperature) per hour so no means of time recovery if data is lost due to power failure. It could be more sophisticated but then it would consume more power!
 

Offline paulca

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Re: UK solar doldrums
« Reply #263 on: January 10, 2019, 08:17:21 pm »
Well, a week before xmas my solar system shut itself off.  I hadn't been able to pull any power from it for weeks.  The battery was down to 11V.  When it shut off I decided it was time to recondition the battery and a good job I did it promptly as the battery registered only 8.8V on the charger.

It's been that bad here through December.  Normally you would get a sunny morning or afternoon once a week, but no.  It's been dead overcast for a month.  When the sun does peek out it's only been for half an hour late in the afternoon through broken clouds.

Unfortunately the 8.8V thing may have harmed the batteries as when condition charged to 14.40V for an hour, then floated at 13.6V for 2 hours, when rested over night they register only 12.8V.  They should register 13.1V.  Still servicable, but I think they took a hit.

The only thing they are running is the charge controller itself and the microcontroller wifi which sends the stats.

I might start switching it off at night when I get home and on again in the morning before I leave until the days get longer.
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 

Offline Zero999

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Re: UK solar doldrums
« Reply #264 on: January 11, 2019, 01:12:06 pm »
What do you expect from a solar system north of 50o parallel? It's only reasonable to expect useful output from April to September.

Being eastwards of a large expanse of a relatively warm ocean doesn't help either, as the moisture will form clouds, blocking out the sun.

Over all 2018 must've been a good year for solar power, as it was the second sunniest on record.


https://www.metoffice.gov.uk/news/releases/2018/weather-review-of-2018
 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #265 on: January 11, 2019, 02:42:31 pm »
What do you expect from a solar system north of 50o parallel? It's only reasonable to expect useful output from April to September.
That sounds a bit negative, I get around 10% of my summer output and that is very useful to me defraying my oil bill. We are not all fortunate to live near the equator but I am more than happy with what I get and so I am sure are many others :)

As for battery problems I was looking for but could not find a thread I saw somewhere recently about someone trying to recover AGM batteries and the story was not good, I am sorry for your troubles Paulca. I think I decided early on for that reason to avoid batteries in my solar experiments as they seem an expensive and unreliable way to store energy so instead I store mine in my hot water cylinder though that is not a suitable solution for everybody.

PS found the thread https://www.eevblog.com/forum/repair/attempt-rejuvenating-old-gel-cell-lead-acid-batteries-with-a-bench-supply/?topicseen

PPS to illustrate the point about power output here is the latest plot I have to hand and it only drops below 0.5Kw/h/day for a few weeks a year, not months as proposed above!
« Last Edit: January 11, 2019, 02:54:24 pm by fourtytwo42 »
 

Offline cdev

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Re: UK solar doldrums
« Reply #266 on: January 11, 2019, 02:52:49 pm »
How can an entire country be better than average? Is that the thermal anomaly? Global warming?
"What the large print giveth, the small print taketh away."
 

Offline paulca

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Re: UK solar doldrums
« Reply #267 on: January 11, 2019, 02:53:07 pm »
fortytwo42... my solar system wouldn't be able to heat a cup of water!  50W panel behind a double glazed window.

However it was successfully running a lot of my battery tech gadgets, including (during our brief 2 weeks of summer) my laptop in the evenings for an hour.
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 

Offline paulca

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Re: UK solar doldrums
« Reply #268 on: January 11, 2019, 02:56:21 pm »
On the battery damage.  I hope they have been that badly damaged.  It's possible though as I checked it last night and in only one week running on the system it has dropped from 12.8V to 11.7V only running a 60mA load.  I haven't done the maths, but that sounds like too much of a drop.

I did change my Wifi router, so there is a small chance the microcontroller wifi is pulling more power.

... or the batteries are not holding charge anymore :(
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 

Offline fourtytwo42

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Re: UK solar doldrums
« Reply #269 on: January 11, 2019, 03:07:50 pm »
fortytwo42... my solar system wouldn't be able to heat a cup of water!  50W panel behind a double glazed window.
Try a thermos flask, you might get enough for a cup of tea when you get home from work  ;D seriously though had you considered a tracking mount on a tripod behind your window or maybe the window is not big enough to follow the azimuth very much. I can get ~150W+ from a cloudy sky if the azimuth is right so that's 15% so you should be able to get 7.5W from your 50W panel certainly enough to float a 12V battery + a small amount of charge. Sounds like maybe you don't have any monitoring system to let you know the state of charge so you end up taking out much more than the panel is able to put in  :-//

Of course if you don't have a real mppt charge controller (not chinese fake) then the panel performance may simply be total cr*p ?
« Last Edit: January 11, 2019, 03:12:47 pm by fourtytwo42 »
 

Offline Zero999

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Re: UK solar doldrums
« Reply #270 on: January 11, 2019, 03:47:30 pm »
How can an entire country be better than average? Is that the thermal anomaly? Global warming?
I'm not sure what you're saying.

The map I posted shows the percentage of sunshine over 2018, compared to previous years, averaged over 1981 to 2010.

The sunshine anomaly last year was due to a prolonged anticyclonic period from April to August. It's not a thermal anomaly because clear skies also increase thermal losses, causing the temperature to drop at night, especially in winter, when more sunshine will often give lower temperatures, both day and night.

Temperature-wise, 2018 was another warm year, the 7th on record, across the UK, going back to 1910 and the 4th warmest for central England going back to 1659, despite a cold spell from February to March.
https://www.metoffice.gov.uk/climate/uk/summaries/2018/annual
https://www.metoffice.gov.uk/hadobs/hadcet/ssn_HadCET_mean.txt

Weather or climate change? No one knows for sure. In the UK, with the exception of 2018 and 2013, summers since 2007 have become wetter and less sunny, than those in the late 1980s to early 2000s. No one knows why. Some say it's climate change and have linked it to increase ice melt over Greenland, others say it's part of a natural cycle. I tend to side with the latter and think increased ice melt over Greenland is more likely to be an effect of the weather pattern which brings increased summer rainfall to the UK, rather than a cause.

 

Offline apis

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Re: UK solar doldrums
« Reply #271 on: January 11, 2019, 09:35:07 pm »
Weather or climate change? No one knows for sure.
You can't know if a single warm year (especially in a local geographical region) is due to random variations (basically noise) or a long term trend. But there is a very clear (i.e. statistically significant) long term pattern of global warming. It is as undeniable as a round earth. And the only theory that fits the data is that it is caused by greenhouse gas emissions, and we know where those come from.

You don't have to take my word for it, a summary of all the science is available on the web here:
https://www.ipcc.ch/report/ar5/wg1/
 

Offline Zero999

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Re: UK solar doldrums
« Reply #272 on: January 11, 2019, 11:19:48 pm »
Weather or climate change? No one knows for sure.
You can't know if a single warm year (especially in a local geographical region) is due to random variations (basically noise) or a long term trend. But there is a very clear (i.e. statistically significant) long term pattern of global warming. It is as undeniable as a round earth. And the only theory that fits the data is that it is caused by greenhouse gas emissions, and we know where those come from.

You don't have to take my word for it, a summary of all the science is available on the web here:
https://www.ipcc.ch/report/ar5/wg1/
Yes, I know. Why do you insinuate I was denying that was the case?

What's also interesting is that the heatwave covered a larger area this year, than previous hot UK summers. However it wasn't hot everywhere: some places were anomalously cooler than normal, such as Iceland and Greenland, which is typical for a positive phase of the North Atlantic oscillation.
 

Offline apis

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Re: UK solar doldrums
« Reply #273 on: January 11, 2019, 11:41:02 pm »
I'm sorry if I misinterpreted you. I though you were saying that it's not possible to know if global warming is just a natural variation or if the earth is actually warming up, but it's very clear it is warming, so I wanted to point that out. In my defence, I've heard all kinds of misconceptions wrt climate change in the past so I jumped to conclusions.
 

Offline paulca

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Re: UK solar doldrums
« Reply #274 on: January 17, 2019, 11:40:19 am »
So my solar system is back to normal.  I believe I read the wrong value which made me think the battery was not holding charge.  I read the "Load schedule" which is always 117, which I read as 11.7V which worried me.  The battery was actually at 12.5V which is more like it for running the solar system with overcast sky for nearly a week.

The charge controller is indeed an MPPT, although a fairly cheap chinese brand it is not an ebay random product, but an epEver 10A controller that I have verified is MPPT.

Anyway we have had a few days now with sunlight at least and the battery was happily floating up to 13.6V for a few hours before began putting load on it again.

Hopefully December was just a dull month here and things will be back to normal ... and the days are getting longer again.  We only really get about 7 hours daylight in December/January.  Out of those hours the sun is only really in the correct alignment for my panel for about half of that time.  It's pulling in 1.5A this morning.  Not that bad for a sun barely peeking over the house roves in front.

Also, I do have monitoring which logs all the parameters once a minute.  However I haven't looked at it in a while and it was offline for about a month due to a new Wifi router from my ISP not supporting my 10.x.x.x IP range.  It's working again though.
« Last Edit: January 17, 2019, 11:43:00 am by paulca »
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 


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