Forum Discussion

BFL13's avatar
BFL13
Explorer II
Jun 19, 2015

Solar --Wire and Battery Fuse Size Confusion- How Big?

Can somebody please explain the math on this? I get really confused. Previously, I have seen how you have to allow 1.25 oversizing for the wires from the panel, the controller, and the wires from ...
BFL13's avatar
BFL13
Explorer II
Jun 24, 2015
Joel_T wrote:
So, if I have a 30amp controller running 2 160watt panels what size circuit breaker fuses will work between controller and battery....30a....50a? (Besides a 40a that is, that are backordered a month and a half.)


Expect 320/130 x 8.2 = 20 amps with panels aimed at high sun at STC so 1.25 that is 25 amps to allow for on wire gauge choice.

Then fuse to what wire gauge you actually picked (overdo the wire to reduce voltage drop.) IMO a few feet of #8 wire and a 30a fuse would work.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,190 PostsLatest Activity: Jan 24, 2025