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Solar cells in series sum voltage and current? Answered

I am very confused!

I built a 10-cell panel (laid out on corrugated plastic for testing). They were rated at 1.8W and .5V. In the sun, putting the volt meter on a SINGLE cell yields about .55 V and 136mA. This is the same for every one I tested, on the panel and individual cells.

What the heck? Shouldn't they be about 3.6A?

So I soldered 10 in series and put the leads across the final terminals- sure enough I get about 5.5 volts! But I also get about .96A. And current is negative.

WHAT THE HECK?!

Am I understanding it wrong? I have to be. I thought putting cells in series adds voltage but current is going to be the same as whichever cell is producing the least. Somehow I'm going from .55V/ea to 5.5V/panel. and 136A/ea to .96A/panel.

10 cells. Should have had an 18W panel. Each cell should be giving me 3.6A. "This should be fairly simple" I thought.

Discussions

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Qcks

5 years ago

EHhh.... is 1.8 watts and .5 volts idealized or actual?
Cause solar panels are only supposed to be something like 25% efficient. If the wattage rating was giving an idealized number, it's very easy for their actual output to be quite a bit less.
Small amounts of dust/grime, improper angle towards the sun, heat...these are all things that can drop the efficiency.

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mpilchfamily

5 years ago

The cell specs are wrong/missleading. Wish solar power was fairly simple and straight forward but it's not. All specs are best average case and rated open circuit. But everything will vary based on sun exposure, ambient temp and overall load on the cell.