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Old 11-24-18, 11:34 AM   #1
where2
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Default Panel misbehaving

For a few weeks now, I've had one panel misbehaving with an output down around half the daily energy of the others in the system. Following Pinball's instructions in another thread, I reset my microinverter yesterday to see if a reset had any positive results.

When I first noticed this panel had an issue, the thing I noticed was that the output voltage looks to be ~33% below normal. I'm using 60 cell panels, which seem to run 24-26V when the microinverters are running their MPPT algorithm. This misbehaving panel is running around 17V, while the panel next to it is running 24V. Recognizing each panel contains bypass diodes, this leads me to a hypothesis that one of the three bypass diodes is not functioning.

These are Evergreen panels, purchased for $0.78/W after Evergreen went belly up. I'm on my own as far as remedies at this point. (However, I knew that 6+ years ago when I bought the panels). If it's just a blocking diode issue, Newark or Digikey should easily be able to get me up and running again with a replacement diode at minimal cost.

I figured I would post my hypothesis, and see if any of the other PV users have had any similar issues with their systems? I'll go up on the roof and see if I can check that panel with a digital volt meter, if I can get the cover off the back of the panel where the diodes live.


Last edited by where2; 11-24-18 at 12:32 PM..
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