Fuse melting mystery in simple solar setup

[EkeneDili]

I have a 180Ah 12V Varta battery connected to a Victron solar controller (also tried Triron) and 2x 240W flexible panels. The load (14W) runs overnight, but my inline fuse keeps melting every few days, I tried 5A to 40A fuses. Why?

 

[RobertP-50]

I have a 180Ah 12V Varta battery connected to a Victron solar controller (also tried Triron) and 2x 240W flexible panels. The load (14W) runs overnight, but my inline fuse keeps melting every few days, I tried 5A to 40A fuses. Why?

I encountered a similar issue when my fuse kept overheating, and it turned out to be a loose connection, causing resistance and heat buildup. If your wiring is secure, check if the fuse holder is rated for the current. It may be undersized. A DC clamp meter can help identify an unexpected spike in amps. Have you noticed any discoloration or warping around the fuse? That could point to excessive heat.

 

[EkeneDili]

I encountered a similar issue when my fuse kept overheating, and it turned out to be a loose connection, causing resistance and heat buildup. If your wiring is secure, check if the fuse holder is rated for the current. It may be undersized. A DC clamp meter can help identify an unexpected spike in amps. Have you noticed any discoloration or warping around the fuse? That could point to excessive heat.

Thanks, that makes sense, I'll double-check all connections and the fuse holder rating, there is no discoloration yet, but I'll grab a clamp meter to catch any current spikes overnight

 

[RobertP-50]

Thanks, that makes sense, I'll double-check all connections and the fuse holder rating, there is no discoloration yet, but I'll grab a clamp meter to catch any current spikes overnight

I'm hoping you were able to sort out that melting fuse situation. Did you find out if it was a bad connection or an undersized fuse holder after all?