This one is a multi-pixel-temperature-o-meter!
It will be the subject of a blog post, and probably featured in others, but I got it to help run down some faults in my solar array.
This is a normal junction box while running.
This… might indicate a problem!
And, interestingly, on my south facing array, I’ve definitely got a shorted bypass diode!
Anyway. Review coming soon, and probably another 10k word epic on hunting arc faults in solar arrays…
But, seriously. If you’re going to write an error message that applies to a bunch of things, don’t make it specifically state “Thing 1.”
Hm. I don’t think the inside of a junction box is supposed to look quite like that…
Nope. Couple panels are going to be swapped out here soon.
And reworked… I’ve bypassed the entire “use the back plate” thing, and made an old style junction box with bypass diodes.
During testing, I just shorted the panel to load up the junction box. You get some interesting patterns that don’t show up under normal operation - apparently this is just “a thing panels do when shorted,” it highlights minor variances in the cells.
And the revised box, running cool. The “hot spot” to the right of the left main lead is a window to the back of the panel, so it’s seeing the back plastic - it’s not an issue in the box.