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Array configuring for 10 panels with 2 Growatt SPF 3000TL LVM in Split Phase

curt95658

Solar Geek
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Apr 1, 2021
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Sunny Cal
I have 10 used panels from San Tan Solar with VOC 36.7. Right now I have them split into 2s2p(73.4v) into one inverter and 2s3p(73.4v) into the other. The max pv voltage logged so far has been 65v. The Growatts have a max VDC of 145. My question is, should I raise the voltage by reconfiguring it to 3s2p(110.1v) into one inverter and 4s(150.4v) into the other. It would raise the VOC slightly above the rated VDC on the 4s side but the way the panels are mounted on both sides of a well shed/shop roof and are not pointed at the sun it would have no chance of overvoltage. So far the panels run at 65% max. Would re-wiring the panels raise the efficiency?
 
I have 10 used panels from San Tan Solar with VOC 36.7. Right now I have them split into 2s2p(73.4v) into one inverter and 2s3p(73.4v) into the other. The max pv voltage logged so far has been 65v. The Growatts have a max VDC of 145. My question is, should I raise the voltage by reconfiguring it to 3s2p(110.1v) into one inverter and 4s(150.4v) into the other. It would raise the VOC slightly above the rated VDC on the 4s side but the way the panels are mounted on both sides of a well shed/shop roof and are not pointed at the sun it would have no chance of overvoltage. So far the panels run at 65% max.

Panels don't need full sun to produce max voltage and temperatures below 77°F cause panel voltage to increase. Absolutely, positively do not go 4S. You should never get near the PV max voltage limit when putting panels in series.

Would re-wiring the panels raise the efficiency?

No. Efficiency is a trade off. The higher your PV voltage difference from your battery, the less efficient, BUT your PV wiring may be more efficient depending on length and gauge of cables. The Growatt MPPT aren't particularly efficient, so going to higher PV series voltage may not benefit you unless your PV wiring has excessive losses.
 
Thank you for the well-thought-out response, I will definitely take your advice. Thanks again. Curt
 
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