HI Ron, I have seen this a few times. And just a month or so ago.
You can measure VOC and its right. You can measure ISC and its right, but no power. As someone said, there is a weak/bad connection. Usually its on a main ribbon. Its just barely making connection. Enough you can get VOC. And when you go for ISC with good sun, it’ll arc and give you good connection there. But for reasons I don’t understand, it doesn’t always make that connection for power. I even had one module that if you shorted it (ISC) and then connected it to load it would work, but next morning, nothing. I’d check the junction box first, but you might also find something in the main ribbon connections. A thermal gun might find it. good luck, jay peltz power sent 7:37am 9/16/15 > On Sep 15, 2015, at 8:30 PM, RM You <solarea...@solareagle.com> wrote: > > Just wondering if any esteemed wrenches have an idea what could cause this > problem? Customer says nothing unusual happened that he is aware of and the > panels had been working fine for many years but now 4 of 6 panels just quit. > Doesn’t appear to be a diode failure. > > Ron > >> On Sep 11, 2015, at 4:58 PM, RM You <solarea...@solareagle.com> wrote: >> >> I have a customer who has 6 siemens 48w panels that are 20 years old (hooked >> in parallel to a 12v battery). He says that 4 of them have failed in that >> there is no output unless he bypasses the diodes. However he pulled the >> diodes and checked them on a diode check and separately on a battery with a >> light bulb and they appear to be functioning correctly. Any ideas what could >> be causing this anomaly? >> >> Ron Young >> > > > _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
