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PV Panels watts in relation to voltage


Warlok
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Good day to all,

I had 3 Canadian solar panels (CS3W-400P), but now only have 2 due to a hail storm.

Pmax=400W

Vmp=38.7V

Imp=10.34A

Voc=47.2V

They were connected in series giving me about 1.2kW and 115V, give or take. Now with 2 panels connected in series I only get +/- 500W and 70V. Max input to the inverter is 145V.

I was expecting 800W, but is the lower voltage responsible for the lower wattage? I'm totally buggered at the moment due to the lock-down.

Is there a way to get more watts out of the panels as they are? or could it be that the hail impact on the 2 remaining panels caused something. They have no physical damage and the voltages seem right.

On a more or less similar note. My brother has a Growatt 3kw inv paired to 3x330w panels connected in parallel.

PV voltage it can handle is 100v and max pv watts is 1000w. He too is only getting about 500w at 32v on a good day, so I told him to connect it in series, but he told me the mppt controller should work things out.  I have checked the Voc on the sticker and its just below 100v. Did I just answer my own stupid question or is there more to it?

If Coulomb is reading this, thank you very much for all the input you have given on this forum.

Thanks for a great forum

ps. Anybody want a good second hand slightly used hail damaged solar panel? Willing to swop for toilet paper.

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51 minutes ago, Warlok said:

I was expecting 800W, but is the lower voltage responsible for the lower wattage?

No. 70 V is perfectly fine for a 145 V max (130 V max for maximum power) solar charge controller.

I suspect you rarely got 1.2 kW from your nominally 1.2 kW panels. Usually the best you can expect near noon if the angles are good and no cloud or shading is about 80% of nominal, sometimes 75%. So that's around 600-640 W. 

I suspect the other panels sustained some damage from the hail, even if not as visibly bad as the one in your photo. That might explain the last 100 or so watts.

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27 minutes ago, Coulomb said:

No. 70 V is perfectly fine for a 145 V max (130 V max for maximum power) solar charge controller.

I suspect you rarely got 1.2 kW from your nominally 1.2 kW panels. Usually the best you can expect near noon if the angles are good and no cloud or shading is about 80% of nominal, sometimes 75%. So that's around 600-640 W. 

I suspect the other panels sustained some damage from the hail, even if not as visibly bad as the one in your photo. That might explain the last 100 or so watts.

 

20200411_152814.jpg

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24 minutes ago, JustinSchoeman said:

Some suppliers (eg Solar Man in Pretoria) are still open, but for spares and repairs only (under the essential maintenance provision).  So it should still be possible to order replacement panels during the lockdown.

Thanks Justin. Will take a look, but I would really like to support the power-forum store. https://powerforum-store.co.za/

Suppose it all depends on price...

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