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Comments on How to check realistic specs of small solar panel?

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How to check realistic specs of small solar panel?

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I have a small solar panel rated for 6V/DC, 150mA. I know that those specs are under ideal circumstances, and I would like to do some measurements in different weather conditions to see what I can expect.

To measure voltage I can of course use a multimeter. For current, I think I know what to do, but I just wanted to check. Can I simply make a circuit like below to draw a variable current, and adjust the potentiometer to find the maximum current that can be drawn before the voltage drops significantly? Or is there a better or simpler way?

Circuit of a DC voltage source with a 22 Ohm constant resistor and 100 Ohm potentiometer in series.

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For a "better way", research Maximum Power Point Tracking (MPPT.)

The solar cell will produce some number of Volts and Amps. But the amount of power (V*A, Watts) a solar cell produces is not simply "when one is at maximum."

For instance, the most current will happen when the load resistance is lowest. But the Volts will also be really low, so little power will actually be generated. Conversely, very little load will give a higher voltage, but lots of volts and little load also equals little power. A MPPT draws the optimal current at any given illumination so that the most power is delivered from the cell.

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Also in production? (2 comments)
Also in production?
Keelan‭ wrote almost 2 years ago

Do I understand this correctly that you would not only use the MPPT for measuring out what I can expect, but also "in production"? The MPPT itself also uses some power, so are you saving more than what it costs?

rdtsc‭ wrote almost 2 years ago

MPPT is definitely used in production. It's not really efficient for a single cell, except for testing.