How to determine panel info?

[Rednecktek]

OK guys, my neighbor has a mix of 2nd and 3rd hand panels at his place and not a one of them has a data sticker or model number on it. I know I can stick it in the sun and throw on a DVM to get an idea of the VoC which will tell me the nominal voltage (I'm thinking they're all 12v-ish, but he does eat controllers pretty regularly), but what would be the simplest way to get the max amperage to determine the wattage? Do I plug a heavy DC load into it and check it with an amp clamp to see how much it's drawing? Is there a better way?

Thanks guys!

 

[mikefitz]

Measure the open circuit voltage with a meter and the short circuit current with a suitable meter, ideally a DC clamp meter.

Measure the physical size and compare with advertised panels. For a given area the outputs are similar.

Mike

 

[Rednecktek]

So just throw the amp clamp around a wire and touch the ends together? Doesn't that damage the panels?

Yes, I have a DC amp clamp for all this.

 

[upnorthandpersonal]

Doesn't that damage the panels?

No. Shorting a panel does not damage it. Shorting a string that is part of multiple parallel strings on the other hand is a different thing - that's why you need to fuse when you have more than two strings.