Solar PV advice

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nowty
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Re: Solar PV advice

#221

Post by nowty »

sharpener wrote: Thu Mar 13, 2025 3:45 pm PVGIS enables you to predict generation by site/orientation/pitch, I don't know the underlying theory exactly but I think it is based on geometry not measurement. Solcast makes short term predictions based on weather forecast, Victron use it in their adaptive ESS algorithm but ATM I have got it turned off.
PVGIS is more than just geometry,
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Richard77
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Re: Solar PV advice

#222

Post by Richard77 »

Generation is tanking now with a bit of shade...

Image

200w
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Joeboy
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Re: Solar PV advice

#223

Post by Joeboy »

Richard77 wrote: Thu Mar 13, 2025 10:02 am
Countrypaul wrote: Thu Mar 13, 2025 9:23 am You would normally expect a 2.58kWp array to produce upto 2.58kW. The temperature of the panels would have to be as specified in the panel documentation and the insolation usially 1kW/m2. If the weather is very cold then you might get slightly more, if very warm less - again the panel documentation should give you an idea of temperature degradation.

Getting 663W out of a 2.58kW array looks like it gives you the 25.7% figure you are seeing.
Thanks Countrypaul...

I was thinking (wrongly I suppose) that as the solar panels efficiency is around 23% I would only be able to generate 23% of the 2.58kw :oops:

So if everything is perfect I should be able to generate the full 2.58kw (never going to be perfect in NW England though!)?
Let us know what it puts out close to midday on a decent unshaded day? Congratulations BTW. 👏
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Re: Solar PV advice

#224

Post by Richard77 »

Cheers Joeboy :xl:

It was getting 1257w max today around midday. It was pretty clear and sunny at times today.

Unsure if the tigos are working as they should though as it seems to have plummeted as soon as a bit of shading. I don't actually know what the optimiser is supposed to do so will have to have a Google it hehe.

Image

Shame can't put batteries in yet though, as garage doors aren't going in til April 8th... Don't fancy someone wheeling them away!
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Re: Solar PV advice

#225

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Richard77 wrote: Thu Mar 13, 2025 4:42 pm Cheers Joeboy :xl:

It was getting 1257w max today around midday. It was pretty clear and sunny at times today.

Unsure if the tigos are working as they should though as it seems to have plummeted as soon as a bit of shading. I don't actually know what the optimiser is supposed to do so will have to have a Google it hehe.

Image

Shame can't put batteries in yet though, as garage doors aren't going in til April 8th... Don't fancy someone wheeling them away!
That's pretty good. You should see system peak in May before cell heat itself becomes a variable. If I was getting close to 50% across the board at this time of year I'd be happy.

Are they two strings of two in series as a set up? Or are they 4 independent panels running on optimisers?
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Re: Solar PV advice

#226

Post by Richard77 »

Joeboy wrote: Thu Mar 13, 2025 4:51 pm
Richard77 wrote: Thu Mar 13, 2025 4:42 pm Cheers Joeboy :xl:

It was getting 1257w max today around midday. It was pretty clear and sunny at times today.

Unsure if the tigos are working as they should though as it seems to have plummeted as soon as a bit of shading. I don't actually know what the optimiser is supposed to do so will have to have a Google it hehe.

Image

Shame can't put batteries in yet though, as garage doors aren't going in til April 8th... Don't fancy someone wheeling them away!
That's pretty good. You should see system peak in May before heat itself becomes a variable. If I was getting close to 50% across the board at this time of year I'd be happy.

Are they two strings of two in series as a set up?
They are 1 string with 4x 645w aiko panels (hopefully... Can't find a model number on them!) in series. I thought it would be best to do that otherwise the startup voltage would be too low if just 2x panels. So I suggested doing that to the installer. Again...I can only assume that's what was done.

They each have a tigo ts4-a-o on each panel (did see them underneath panels but again they look like tigos but god knows hehe).

Both sides of roof are very low pitch and they both get the sun at exactly the same time so thought would be ok all on 1 string.

That leaves 3 empty strings in the future for the 3 roofs on the house.
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Re: Solar PV advice

#227

Post by Joeboy »

Sounds good. I have solaredge optimisers on one of the set ups and the panels do vary. As you'll be able to see all four panel outputs (I hope) in your software. Keep an eye out for one dropping when shaded and the other three output remaining high.

If one panel is shaded and all drop to the same value then you'll want to look into that. Don't freak out, I'm sure all 4 panels are doing their independent thing but worth confirming?
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Re: Solar PV advice

#228

Post by Richard77 »

Joeboy wrote: Thu Mar 13, 2025 5:23 pm Sounds good. I have solaredge optimisers on one of the set ups and the panels do vary. As you'll be able to see all four panel outputs (I hope) in your software. Keep an eye out for one dropping when shaded and the other three output remaining high.

If one panel is shaded and all drop to the same value then you'll want to look into that. Don't freak out, I'm sure all 4 panels are doing their independent thing but worth confirming?
I couldn't find anything in the menus for each individual panel (SunSynk connect)... Just how much they all generate together.

I might do a bit of testing tomorrow if it's sunny with some cardboard and cover certain panels and see what changes.

I was looking at voltages in the software today and thought that would be around 200v all the time. Each panel voc was 50v or 54v I think from the datasheet. So thought with all 4 working the input voltage would be around the 200v. It did seem to be around 150v most of the day though. :whako:

Image

Seems it did jump to 200v+ on a few occasions.
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Re: Solar PV advice

#229

Post by Richard77 »

Total generation today was 4.00kWh.
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Joeboy
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Re: Solar PV advice

#230

Post by Joeboy »

Richard77 wrote: Thu Mar 13, 2025 6:12 pm Total generation today was 4.00kWh.
Our W/E system at 5.12kW produced 10.7kWh. That's the one with optimisers on. The other system that is very close to being the same size (5.12kW) has a Southerly heading (mostly) and it kicked out 14.75kW. This indicates to me that HP matters which is orientation.

No1 Son system at 800W produced 0.92kW today and is Southerly. On its best day of the year it will produce 6kWh.

4kWh is decent for a smaller system which is also mighty. I think you'll be pleasantly surprised. Welcome to the club!
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