Panel reversed polarity -- now outputs half rated voltage and zero amps

andybaird

A friend bought a 180W 32V panel. When connected to a Victron controller, it didn't work. Investigation revealed that the leads from the panel had been mislabeled--positive was labeled - and negative was labeled +. When the reversed polarity was corrected by switching the leads, the panel was found to be putting out exactly 16V and 0 amps. 

A replacement panel was shipped by the manufacturer and it works normally, proving that the Victron controller was not damaged. There's no visible damage to the nonworking panel, but its junction box is potted with white stuff--probably silicone rubber--so it's not possible to examine the diodes or measure voltages on the two flat leads from the panel to the j-box. Grrr!

Questions: Is it possible that the panel itself (that is, not the j-box) was damaged by the reverse-polarity incident? Damaged in such a way that it only puts out half its rated voltage? Or is the j-box the culprit?

I have not yet gotten hands and eyes on the panel, but I hope to provide more specifics soon. Meanwhile, if anyone has seen similar behavior after a reverse-polarity incident, I'd like to hear about it. Thanks!