Quote:
Originally Posted by roflwaffle
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Ding ding ding! Except not one, but "one and a half."
Did a bit of research, and
the panel does have (used to have) built-in bypass diodes.
Had to do a bit of learnin': I knew what a blocking diode was, but not a bypass diode.
Bypass diode: If part of the panel is in shade, current will back-feed into the shaded cells, reducing panel output and potentially damaging the shaded cells from overheating. A bypass diode shunts current around the shaded cell(s) (its resistance increases so the current seeks the path of least resistance through the diode). This panel has one bypass diode per string of 18 cells.
The first diode I dug out yesterday had clearly blown apart when I shorted the panel. But I dug up the 2nd one this AM and discovered
it had fused together, creating a dead short around half of the panel - thus the 1/2 voltage. (Yesterday when I soldered the first diode together - not realizing it was a diode - I then had shorts around both strings, thus 0 volts.)
So I separated it the fused diode and the panel has full output again. Now I just need to replace 2 diodes ... and get a fuse.
Thanks for the tips everybody.