Author Topic: How does one test a solar panel?  (Read 258 times)

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Offline DaleReid

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How does one test a solar panel?
« on: July 09, 2020, 09:08:50 AM »
With more solar panels used to power the sensor arrays and heavier power users such as fans and such, I'm wondering how do we test a panel to see if it is working?

I know that pulling the plug on the panel and testing the voltage is the first step.

But as has been pointed out, a no-load voltage may be significantly different from what the producing the design current load at a voltage is too.

So for a small panel, the first step would seem to be to know what the expectation for both voltage and current would be.  I'm not sure I've ever seen a panel on a Davis or Rainwise tell me what that should be.

If we want to test the load, I assume a power dissipating rheostat would be helpful, with a voltage and current meter in the test loop and gradually increase the load.

Has anyone experience with the results of testing a bunch of panels, with the setting where a 12 volt panel showed say 14 volts at no load, 12 volts at 1/4 of an amp, and they were good?  I'm thinking that the ability to produce voltage is likely to be a good indicator of the panel testing good, but I don't know with zero experience in knowing how these things fail.  They are too expensive to just do the pull, replace, try and then move on to the next thing if that didn't work.

I'm looking for guidance as I pass by my bench where four panels are sitting there wondering how I can test them correctly.

Pulling a station down, fiddling with it to try to find out why power isn't available, and then putting it back up to only find the problem wasn't fixed is not the most fun part of the hobby.

Offline Kev

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Re: How does one test a solar panel?
« Reply #1 on: July 16, 2020, 07:09:55 PM »

I am not sure if this will be of any help, since it is for another solar panel system, but it outlines how to test the panels under operating current and other variables. It looks like it may possibly be adaptable to your scenario.
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