Quick test for used panels.

TnAndy Solar Expert Posts: 249 ✭✭
I have a chance to buy some used Sharp panels that are rated at 224w, but the guy selling them says they were removed from service after 3 months due to low wattage output....and no, I don't know why they didn't just go back on Sharp with them, since the tolerance is minus5%/plus 10% on them.

Story I get from him is they were part of a large, commercial install.....multiple arrays of 16 panels each, "putting out 4kw" according to him....though I don't see HOW you would ever get 4kw out of 16 x 224w.....even with the +10%, that seems unlikely in real world condition ( non-STC )....he said one array was "only putting out 3.3kw, so it was removed " ( quoting him ) Well....3300 watts sounds pretty good to me for 16 panels with a PTC rating of 198w.....my suspicion is they had a combiner/wiring/connection issue if one array of 16 was that much lower than other arrays of 16....but whatever...

ANYWAY, he selling them as 185w panels, and I can get them at real good price
even at 185w.

My QUESTION: Is there a simple way to check output on each panel if I go to pick them up on a good sunny day.....what could I take with me and connect quickly to each panel leads to give me a 'down and dirty' idea so I don't get home and find I've bought a bunch of dud or damaged panels ?

Thank you all !


  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Quick test for used panels.

    you can check the open circuit voltage and short circuit current to see if it matches the specs, but it must be very sunny and aimed well.
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Quick test for used panels.

    Better be cheap, you can get new panels for under $2.40 watt , under 2 bucks if you don't need UL stickers .. keep that in mind when your buying used