Circuit breaker setup

simmtron

I'm just curious about setup of circuit breaker between charge controller and batteries. I have a breaker from Auto zone and one terminal says Bat and one says Load. Now normally I would think the charge controller should be thought of as Battery and the batteries as Load as that is the way the current is going. BUT, I was thinking the circuit breaker would be better protecting charge controller from the batteries if a short came from the batteries. Just wondering best way to hook up as I guess the circuit breaker will trip one way better than the other. Or maybe it doesn't matter? Any opinions?

BB.

Your second thoughts are correct. The circuit breaker is protecting the wiring from the current provided by the battery bank. (solar panels, the circuit breaker protects the "shorted panel" against the other parallel panel strings).

There can be an issue with many DC circuit breakers... They are designed to stop the short circuit current in one direction only. They can have a permanent magnet near the contacts. The magnetic field will "blow the arc" away from the contacts and into the arc channel/quenching channel. If the current flow is "reversed", the magnet can pull the arc into the mechanics of the breaker.

Newer breaker standards are requiring DC breakers to work correctly regardless of the direction of the current flow.

-Bill

simmtron

I have the batteries fused that go to a bus bar and from the controller to the bus bar the circuit breaker.

Estragon

I suppose you could get away without the breaker then, but the breaker are handier to depower when need be.

simmtron

Yes I really use the circuit breaker mostly for shutting power to the charge controller.