Hello,
I would like to get your thoughts on a problem I have with my Kyocera 50 watt panel that I bought in 1999. I used it on my RV for years with no problem, and it has been hanging in the garage for 5 years. I thought I would start to use it to charge all my electronic devices, so I put it out in the sun and connected it to a deep cycle battery. It was charging 2 amps for a while, then I noticed that the current was varying a tenth of an amp or 2 and at the same time kept getting less. After a half hour it was down to less than a tenth of an amp even though the battery voltage was still about the same at 13 volts. Sounds like a typical case of a loose connection like I read about in these forums, right? Well, yes except for what happened next: I disconnected the panel from the battery and measured the open circuit voltage, which looked right at about 18 volts. Then I measured the short circuit amps, which looked about right at 3 amps. Then I connected the panel back onto the battery and it was back to charging 2 amps again and the cycle began over again. In another half hour the current was back to 0.1 amp. And I can keep doing this: short the panel for a second and the panel works for half an hour. This is in the bright sun at midday with about 80 degree air temperature. I have checked the setup and connections a dozen times and am confident that it is in the panel – but where, and can it be fixed? It sounds to me like a problem in the semiconductors themselves. What do you think? There is no controller in the circuit and no bypass diode.
By the way, I am an electrical engineer from way back, and I have a lot of troubleshooting under my belt == but this has me baffled.
