Author Topic: EEVblog #724 - Home Solar Power System Analysis & Update  (Read 46608 times)

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Offline mtdoc

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #75 on: March 17, 2015, 03:05:39 am »
Another point to consider on panel price/watt. The recent trend is to make bigger and bigger panels. The main advantage is it can save on mounting hardware, wiring, etc. Since panel prices have bottomed out - saving on installation BOM hardware costs have driven companies to market larger panels.

The downside is they are more difficult and unwieldy to install!
 

Online free_electron

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #76 on: March 17, 2015, 04:50:15 am »
I had to go out and clean snow off the panels several times.

Snow? What's that? I don't understand...

i heard it is state of water and falls from the sky. i vaguely remember water  droplets falling from the sky, but those were in liquid form.

I also heard stories about some people that go in search of it on mountains tops and strap wooden slats , kinda like 2 by 4's , to their feet to use it to glide very fast back down the mountain. I guess it must be to make up for the time wasted climbing the damn things, and searching for this fabled substance, in the first place.
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline bills

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #77 on: March 17, 2015, 05:56:36 am »
I had a 3 kw system installed 8 years ago,it was costly $20k with rebates and tax credit it cost $12k ( I refused to pay the last $3k until they made it produce 3k it will make 2.5k on a good day)
My bill was $300.00 per mo. in summer $80-$100 for the rest of the year,now my power bill is $300.00 to $400.00 per year. still  only makes 2- 2.5 kw. so for $9k I am happy.
BTW they never tried to collect the $3k.
All components were mfg. by sunpower and have a 20 year  warranty.
Never argue with idiots. They drag you down to their level and beat you with experience.
 

Offline rs20

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #78 on: March 17, 2015, 06:32:20 am »
I had a 3 kw system installed 8 years ago,it was costly $20k with rebates and tax credit it cost $12k ( I refused to pay the last $3k until they made it produce 3k it will make 2.5k on a good day)
My bill was $300.00 per mo. in summer $80-$100 for the rest of the year,now my power bill is $300.00 to $400.00 per year. still  only makes 2- 2.5 kw. so for $9k I am happy.
BTW they never tried to collect the $3k.
All components were mfg. by sunpower and have a 20 year  warranty.

Did they actually try to deceive you by saying that a 3kW system produces 3kW? Do you have a sun-tracking installation? Because everyone knows that the nominal watt figure on these panels are under extremely idealised, artificial circumstances.
 

Offline bills

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #79 on: March 17, 2015, 06:51:20 am »
no they said i would get 3kw i did not!
They told me that they fired the salesman ( I don't care I was  expecting 3kw) I told them I needed at least 2 more panels to get the required out put and offered to pay extra for them, they dropped the ball and it cost them.
Never argue with idiots. They drag you down to their level and beat you with experience.
 

Offline bills

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #80 on: March 17, 2015, 06:54:13 am »
BTW I have 2 panels 250w on order to fix it myself. my existing panels are 235w hope these will work.
Never argue with idiots. They drag you down to their level and beat you with experience.
 

Offline C222

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #81 on: March 17, 2015, 08:44:34 am »
Hey everyone.
I work at a solar power provider and took some halfway decent images of our solar inverter testing setup.
Where would be the best place to share the album? New topic? Which subforum?

 

Offline G7PSK

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #82 on: March 17, 2015, 01:20:14 pm »
When we put the house up for sale one of the questions asked by the solicitor was is there a solar panel on the roof. When I asked why this question was there I was told that Mortgage company's do not like them especially if they were installed by one of those company's that install them at no cost in order to get the feed back tariff.
 

Offline SNGLinks

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #83 on: March 17, 2015, 04:38:44 pm »
When we put the house up for sale one of the questions asked by the solicitor was is there a solar panel on the roof. When I asked why this question was there I was told that Mortgage company's do not like them especially if they were installed by one of those company's that install them at no cost in order to get the feed back tariff.

The company that fitted my free solar panels state on their web page:

Over 3,000 homes have already been sold with our free solar panels installed on the roof and we have never had any problems arise with new homeowners. The Energy Saving Trust estimates that homes with solar sell around 30% faster than homes without.

 

Offline G7PSK

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #84 on: March 17, 2015, 06:16:38 pm »
When we put the house up for sale one of the questions asked by the solicitor was is there a solar panel on the roof. When I asked why this question was there I was told that Mortgage company's do not like them especially if they were installed by one of those company's that install them at no cost in order to get the feed back tariff.

The company that fitted my free solar panels state on their web page:

Over 3,000 homes have already been sold with our free solar panels installed on the roof and we have never had any problems arise with new homeowners. The Energy Saving Trust estimates that homes with solar sell around 30% faster than homes without.

I think the problem arises due to what in effect is a lien on the property it makes a bit more work for the legal team but yes it should not make ant difference at all, my experience with lawyers though is that they are a lazy lot and wont do anything without being chased all the way, if there was any problems the installation company would hardly be likely to advertise the fact.
 

Offline Red Squirrel

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #85 on: March 18, 2015, 07:31:50 am »
Great video, always cool to see these kinds of setups.

I keep looking into going solar, but I really don't think it would be worth it where I live.  I'm in Northern Ontario.  On the other hand for the few months of summer that we DO get, the sun is up at like 4am and goes down around 10pm, so that's a long time if there are no clouds.  So I suppose it could at least offset the cost of AC perhaps?  Or is that a long shot?

I also have to account for the power usage of whatever system I'd setup to get rid of snow.  Some kind of brush system would probably be more efficient than heat.  Or perhaps a piston system that tilts the panels over and lets the snow drop.  The same system could also be used for solar tracking at least on one axis.

Here is some solar insolation data for my area, are those numbers good or bad?

http://pv.nrcan.gc.ca/index.php?n=3143&m=u&lang=e
« Last Edit: March 18, 2015, 07:34:46 am by Red Squirrel »
 

Offline mux

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #86 on: March 18, 2015, 12:08:20 pm »
I get tired of all these people that talk about panels under a buck a watt.  Where are they and would you want to buy them?  Just saw an article about the Australian Govt. Investigating cheap Chinese panels that are failing after three years and that they paid a subsidy for.  With UL, shipping, mounting and wiring there are no cheap panels.

There are zero solar panels I can buy for over $1/Wp (Netherlands). The cheapest ones are about €0.45/Wp, the most expensive ones (e.g. Yingly Panda YL275-C) are about €0.80/Wp. At current exchange rates $1~€1. Even exotic panels like the Sanyo HIT 240s (which have very high efficiency, to use on super-tight roofs) are below €1/Wp.

Entire installations, including all costs, start at just below €1/Wp. Prices are so low that people often choose for higher quality/all black (=purely cosmetic)/fake panels (to fill up visually empty space)/additional crap. With all that, average installation prices have dropped from €1.75/Wp to €1.55/Wp in the past 12 months in the Netherlands.

This is all without any subsidies, including import taxes (that are useless because prices have dropped so much since, that panels are cheaper than they have ever been). You can get about €0.20/Wp effective rebate on your entire installation if you ask for VAT back (which is a subsidy for solar right now).

The US has always been significantly more expensive with solar, and not for any obvious reason afaik. You use the exact same panels, same inverters, not much is technically different. Subsidies and incentives have been astronomical in the US over the last 10 years, waaaaay more than we've ever had in Europe. First Solar and Solyndra being two of the main examples, getting a combined $1B in tax breaks and subsidies, not to speak of the big govt. expenditures on california's (world-leading) solar farms. The subsidies in Germany pale in comparison to that. So you can't blame the government.
 

Offline nctnico

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #87 on: March 18, 2015, 08:44:12 pm »
Yep.  And if you bought them for that price you'd be paying over twice as much to get 16% efficiency instead of 15% efficiency. Not worth it. Like anything else, there's a lot of marketing hype with solar panels.
Unless you are really limited on space it almost never makes sense to pay a premium for higher efficiency panels. In the case of the LG Mono X versus another panel - say a Sanyo panel at $0.71 per watt (15% efficiency),  the same sized array would take up minimally more roof space.

It's not about efficiency, it's about build quality and local warranty support.
It's a much safer bet that LG will produce better quality panels than WunHungLo on ebay, and they'll be around in 20 years time to use that warranty if needed.
That's why I paid more.
I'm not sure whether that is good reasoning. A cheaper panel may have a shorter life but overall the total cost may be lower. By the time the cheaper panel needs to be replaced better panels are probably available so all in all you may do much better getting a cheaper panel. IMHO the time to recoup the investment should be around 5 years (preferably less). Besides that you pay for the warranty as well.

BTW: nice to get back on the solar panels and show some numbers. Do realise that -unlike people in the US and Europe- you are in area with a lot of sunshine. I don't like the way they fed the cables through the roof tile. When I fitted my airco I used a special feed-through tile which is much more wheater proof.
« Last Edit: March 18, 2015, 08:49:50 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline mtdoc

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #88 on: March 18, 2015, 09:02:36 pm »

I'm not sure whether that is good reasoning. A cheaper panel may have a shorter life but overall the total cost may be lower. By the time the cheaper panel needs to be replaced better panels are probably available so all in all you may do much better getting a cheaper panel. IMHO the time to recoup the investment should be around 5 years (preferably less). Besides that you pay for the warranty as well.

Good points. As far as warranties go - they do not vary much among manufacturers. The standard is 80% of STC rated output at 25 yrs.

Quote
Do realise that -unlike people in the US and Europe- you are in area with a lot of sunshine.

Not exactly. It depends on where in US or Europe. Much of the US southwest has equal or greater solar insolation than Sydney and I think that's true for parts of Europe (Spain?).

But -because of the drop in PV prices - this is less important that it once was. More PV can compensate for less sunshine at a modest additional cost.
 

Offline nctnico

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #89 on: March 18, 2015, 09:18:55 pm »
That may be but AFAIK large parts of Australia are closer to the equator than Spain (which stretches furthest to the south compared to other European countries) or the southern parts of the US.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline mtdoc

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #90 on: March 18, 2015, 10:27:56 pm »
True, but it's not just about latitude. It's also about average cloud cover.
 

Offline LabSpokane

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #91 on: March 18, 2015, 10:36:10 pm »
True, but it's not just about latitude. It's also about average cloud cover.

Yup. Which is why the SE and SW regions of the USA have very different insolation values at the same latitude.
 

Offline mtdoc

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #92 on: March 18, 2015, 10:42:50 pm »
And because of the drop in PV prices, even I, living in the top left of that map can produce more electricity for less money spent on PV than someone could 5 years ago living in the bottom left of that map. (and I don't have to worry about a water shortage  ^-^)
 

Offline C222

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #93 on: March 18, 2015, 11:36:09 pm »
and I don't have to worry about a water shortage

Or cleaning your panels!   :D

It's also amazing how sensitive some of the newer panels can be. I've heard stories at the office about my department pulling their hair out because they were getting power generation measurements from a house well after sunset.
Turned out, the house was across the street from a baseball field with its powerful lights on during gametime. That was enough to wake up the solar inverter and produce power.
« Last Edit: March 18, 2015, 11:39:44 pm by C222 »
 

Offline mtdoc

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #94 on: March 19, 2015, 12:14:11 am »
It's also amazing how sensitive some of the newer panels can be. I've heard stories at the office about my department pulling their hair out because they were getting power generation measurements from a house well after sunset.
Turned out, the house was across the street from a baseball field with its powerful lights on during gametime. That was enough to wake up the solar inverter and produce power.

Yep, I've also seen measurable output from a full moon!
 

Offline reagle

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #95 on: March 19, 2015, 01:59:21 am »
I get tired of all these people that talk about panels under a buck a watt.  Where are they and would you want to buy them?  Just saw an article about the Australian Govt. Investigating cheap Chinese panels that are failing after three years and that they paid a subsidy for.  With UL, shipping, mounting and wiring there are no cheap panels.
My Sunpower ACPVs ended up around $1.4/W installed after NYSERDA grant and Fed/state taxes. Almost there..

Offline SL4P

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #96 on: March 19, 2015, 11:16:39 pm »
How about use a Raspberry Pi as a controller to try to make the best use of the energy during the day?
Huh?
How?
Dave - You're normally pretty fast with these kind of things...
Everything can be made better with an Arduino or RasPi - along with duct tape and hot-snot.
Don't ask a question if you aren't willing to listen to the answer.
 

Offline WBB

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #97 on: March 20, 2015, 01:46:30 am »
How about use a Raspberry Pi as a controller to try to make the best use of the energy during the day?
Huh?
How?
Dave - You're normally pretty fast with these kind of things...
Everything can be made better with an Arduino or RasPi - along with duct tape and hot-snot.

And bailing wire, don't forget the bailing wire. The earth would literally crumble to pieces without the stuff.
 

Offline DrGeoff

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #98 on: March 20, 2015, 03:27:25 am »
Thanks for this Dave. I was hoping to see your solar stats before deciding on the size and type of installation to pursue here (about 10km from you). Have been looking at using micro-inverters, which are essentially an inverter per panel, to reduce partial shading effects.
Was it really supposed to do that?
 

Offline HackedFridgeMagnet

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #99 on: March 20, 2015, 04:29:41 am »
I might have missed this as I watched the video a few days ago.
Did the costs include any rebates or subsidies, such as RECs?
In Australia often the installers did get the client to sign these over as part of the discount price.

Though it is probably cheaper now to install solar than it was before even with the RECs.
 


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