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currie avatar image
currie asked

Different open circuit voltages, same panels, same light conditions

Hello, I have just tested the open circuit voltage of 3 new identical panels 140W-12V Mono in the same light conditions.

Two of the panels read identical voltages whereas the third is always around 1V less.

Is this normal ? I can't find the answer anywhere.


Solar Panel
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2 Answers
currie avatar image
currie answered ·

So two of the panels measure 22.4v and the other one 21.4V. Two came as a pair in one box and one on its own. The one on it's own reads lower plus has a blue tinge (nearest in photo) whereas the other two (one in photo) are black.298847200-780190066459056-8204165861214091586-n.jpg


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klim8skeptic avatar image
klim8skeptic answered ·

While you have your meter out, test your solar panels. before the sun goes away.

Tip, the grass shading the bottom of your panel might affect the Isc reading..

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currie avatar image currie commented ·

Hello klim8skeptic

I didn't test them there. I tested the panels flat on the floor. I even moved them around putting the panel in same place as one that measured higher seconds before with the same result. Same panel always measured less. Not a cloud in the sky. The above photo was just to show the blue tinge. I just want to know if a difference of 1V is normal. It is over 4% reduction !

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klim8skeptic avatar image klim8skeptic ♦ currie commented ·
Test the Isc of the panel, probably more important.
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currie avatar image currie klim8skeptic ♦ commented ·
I am waiting for some fuses for my tester so cant test the current for now. I had bought a tester new with blown fuses !! It just looks different from the other 2 and wondered if there had been a problem in the manufacturing or whether differences like this are normal.
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