Is there a good video showing how to test used solar panels so you can avoid buying defective, damaged or low output panels? Saw the example of a FLIR camera showing damage to the panels as a hot spots...... But I was thinking of a watt meter load test? How could I set it up a test of panels before buying them? Any ideas of where to look for this info?
Used solar panels testing procedure
- Thread starter Philisher
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most perform a voltage test, then an amperage test, and compare to lable...
Set meter to dc volts, measure volts at the terminals, then switch meter to amps, and measure at the terminals again.
Easy.
Set meter to dc volts, measure volts at the terminals, then switch meter to amps, and measure at the terminals again.
Easy.
Amperage is the electrical volume passing the measuring point at that time. If there is no load is there any amperage? I can test a car battery with 12v dc and get 6.5 Amps by your test procedure. But the battery is rated at 800 cold cranking amps. So there is a conflict in logic as I see it. I would think the solar panel needs a load to tell how much electricity it can produce.
This is just an Idea but I have a cheapo MakeSkyBlue SCC it costs like 80 bucks you could hook it to a car battery (not fully charged) and the hook to each panel in the sun and see how many watts it produces. I do this to test my panels when I think something is wrong.
If you tested amps of a 12V battery rated at 800A, with an amp lead, it would fry the meter... most volt meters with amp settings on the leads top out around 10 amps. To test 800 amps, you need inductive testing and a load.
Solar panels are rarely rated over 8 amps each, so the 10a dead short test works through the meter, and is a valid method to test panel output.
williamyjk
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I found that the best way to test used solar panels is to connect the two panels leads together (yes, dead short) and then apply a clamp meter that reads dc amps. Here is an example of a dc clamp meter:
Hedges
I See Electromagnetic Fields!
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When unplugging, the arc could burn the contacts. If you turn panel edgewise to the sun or cover it with something opaque that will greatly reduce the current. Doesn't reduce open circuit voltage much so could still shock you if a high voltage panel or series string, but current is reduced.
I put MC4 and banana plugs on a snap-action knife switch and used that for panel testing. With meter connected to 3 wires (volts, amps, common) I connect panel with switch open, read Voc. Close switch, read Isc.
A load would be needed to get other data points. You could connect a nominal 12V panel to a car battery (don't make sparks near it) and see what current it produces at about 14V to 15V.
Often you're getting less than full sun (1000 W/m) so don't be alarmed if current readings are low.
Hedges
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If it produces 33.1V, that is the no-load voltage it will put on charge controller capacitors and transistors, so better use the reading to stay within Voc limits.
Seems hard to believe, though, if it is the number of cells it is supposed to be. Looks like some models are made with twice as many half cells, which possibly could be wired differently.
Seems hard to believe, though, if it is the number of cells it is supposed to be. Looks like some models are made with twice as many half cells, which possibly could be wired differently.
howieb
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Maybe I should check the battery in my voltmeter.
Bud Martin
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Yep, when the batteries are low the DCV readng will show higher reading than it should be.
What temperature is the panel? Low temp panels can output much higher voltage.
Hedges
I See Electromagnetic Fields!
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125 degrees below zero?
Good point... 11V or a 50% increase would be a very cold panel...
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