[Capflyer]

A few times the 60A circuit breaker on the B lead from my B&C 60A alternator to the starter solenoid has tripped and I am not sure why. I read through an FAQ from B&C and saw many different answers that might cure my problem but nothing definitive. Is using a circuit breaker here the correct thing or other things like a shunt or current limiter? Anyone out there with solution to this?

Thanks

 

[lucky333]

Hot?

Assuming you don't actually have an overload condition that the breaker is saving you from...

I've seen this happen with thermal CBs on the B lead when they get hot (hot day, sun-soaked etc). The 60amp rating must be derated when the breaker is hot. The problem went away when the thermal breaker was replaced with a magnetic-hydraulic one. The Potter & Brumfield website has application notes that cover this effect. Klixon makes aviation-rated CBs as well.

The breaker could also be getting old..

BTW when you say its connected to the starter solenoid, I assume that thats just where you pick up the battery and that the CB is not carrying starter current...

 

[rrd1_99]

Use 80A current limiter

Bob Nuckolls mentions in the 'Connection that an overachieving alternator can easily surpass its rated output in normal operations, so he recommends using a "slow-blow" fuse rated for 80A in that circuit. The 80A current limiter available at B&C Specialty eliminates the "nuisance tripping" while still protecting against fault situations.

Roger