Thread: Testing solar panels

Originally Posted by land864

Is it as simple as disconnecting them from the battery and hooking up the multi meter set on 0-20 Volt and seeing what voltage I get out?

Just measuring the voltage with no load won't tell you much, even very sick panels can generate a decent voltage under those circumstances. I see they are hooked up to a battery bank, in which case a good test would be to - on a nice sunny day - turn some of the boat's big electrical loads on and measure the current out of the array [with a clamp type meter, not with probes!]. Also measure the voltage. You can then work out how much power they're putting out and see if it's in spec.

Anything else isn't going to paint an accurate picture of panel health.

Agreed, one of these is my friend when it comes to solar & figuring out what is charging & when:

1000A True RMS AC/DC Clamp Meter | Clampmeters | Multimeters | Test & Measurement | PRODUCTS | QM1566 | Jaycar Electronics

Originally Posted by Milton477

Agreed, one of these is my friend when it comes to solar & figuring out what is charging & when:

1000A True RMS AC/DC Clamp Meter | Clampmeters | Multimeters | Test & Measurement | PRODUCTS | QM1566 | Jaycar Electronics

how do you use that with solar panels?
ive got one, but never used it on solar

The panels should have rating printed on their backs. You can test the open circuit voltage of an individual panel and providing your ammeter has sufficient range you just bridge the panel output with the ammeter and read the short circuit current. Shorting a disconnected panel won't damage it as that current is not a lot higher than their rated output into a battery anyway. Output will drop if the panel is hot as their ratings are usually measured at a panel temperature of 20C.

to field test most panels I just grab a bulb thats near or the same as the rated wattage of the panel and matches the nominal voltage of the panel (I also wire them up to make a combination of bulbs that make the required load i I dont have near enough on hand) and the look at what the bulb is doing an measure the voltage across the bulb.

to check what its doing with a clamp meter, just clamp the meter on DC over the +ve or -ve lead coming from the panel.

if its got a good regulator attached that will tell you the voltages and amps.

A decent regulator will give you loads of information on what charge your receiving from your panels, then you will know if they are in good condition or not. Remember to check the wiring from your panels to the regulator though if you are having issues.

What amount of power you are using with various appliances and last but not least what state of charge your batterys are in and it will show how quickly your batterys are losing charge when in use.

Here is a regulator we have fitted to our van, there is little guess work if you have one of these.


[ame]https://m.youtube.com/watch?v=ApcU-Ne3K6k[/ame]