diy solar

diy solar

overheated panel fuse?

sendero

New Member
Joined
Oct 17, 2021
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I have a small system with 3 arrays of 3 340W panels each. Each array is handled by an epever mppt controller.

I was check on my SOC and I noticed I was lower than I expected. A quick check of the displays showed that array 3 was not supplying any charge. I have an inline fuse on each array, and the panels are wired in series. I checked the fuse and it looked like it had gotten very hot, the casing was deformed and I expected the fuse to be blown.

But it wasn't. I took the fuse assembly apart and put it back together and its working fine again.

I don't know what actually happened but I suspect that the contract between the fuse and holder developed some resistance and then heated up. I ordered a new fuse holder to replace that one, but don't really know what else I could check or do to determine if I have an ongoing problem.
 
Do you have access to an infra red temp gun? Let it get up and running and shoot the temp on each fuse holder. If one of these things is not like the other...
 
took the fuse assembly apart and put it back together and its working fine again
determine if I have an ongoing problem
I suspect that there was poor contact (high resistance) based on your description

The Beetle Roll is the answer. Old aircooled Volkswagens had ceramic pointy ended fuses. Every now and again you’d ‘roll’ them in place to insure good electrics. You might want to add that to your maintenance list :)
 
Yes you have an ongoing problem. You have bad connections. Inline fuses are notorious for this problem, but it could be your crimps.
If the wire gauge from the panels to the CC are sized large enough to carry the maximum amperes expected from the panels, no fuse is needed. Solar panels are classified as Limited Current Supplies.
Batteries need fuses.
 
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