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Discussion Starter · #1 ·
On El Moto my electric motorcycle conversion, I have a circuit breaker mounted in a small plastic box (so all terminals safe & covered)

I am mounting a charge port next to it (for connecting the battery charger)

1.) When connecting the charge port, should the positive (+) wire (from the charge port) be connected to the Battery side of the circuit breaker or the Auxiliary side?

If it's connected to the battery side, charging could be done with the circuit breaker "main cut-off switch" turned "off"
(if/by doing it this way the whole bike would be dead/off)
If it's connected to the Auxiliary side, the circuit breaker "main cut-off switch" would have to be turned "on" to charge the battery
(if/by doing it this way "some stuff" on the bike would still be live/on)

* The second way kinda makes me nervous

2.) Should there be a small fuse (~10A) wired in-line between the charge port & the circuit breaker? (for added protection?)

* It's carrying a "load" so, I would think so

3.) Should the negative (-) wire (from the charge port) be connected "directly" to the negative (-) terminal if the battery?

* I would think so, where else?

I wanted to see what everyone thought about the "proper" way to do this
…& why?

Thanks, you guys are the BEST

I "really" don't mean to give you'all a hard time


36 Posts
I don't have experience with this particular type of breaker, but if I get it right, it's a dumb mechanical thing - it should not be any difference what terminal you're connecting to. Just in case test it with a multimeter (if there is, say, a diode inside, which I highly doubt).
That's it - once current heats up a bimetallic strip inside the breaker to high enough temperature - it will set off and direction of current doesn't matter.

Add a breaker to the side of a wire, that's closer to the source of electricity. So, if the wire got damaged and shorted, you disconnect the electricity at the very beginning of it.

Place a breaker, that's rated for the max charging current close to the charging port and place another one at the beginning of the discharging cable, that's going from the battery to the motor or whatever.

If charging cable goes directly to the battery terminals, yes - it makes sense to put breakers at the both ends of the cable.
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