Battery cut off switch
I just bought one like the one in the picture below. Should I install it on the positive terminal or the negative and why? I run two 12V group 27s in parallel.
Forum Discussion
DryCamper11 wrote:
The breakaway needs to be wired directly to the battery to function. If it's wired after the switch - regardless of whether the switch is on the pos or neg, it won't work with the switch off. If the switch is on the neg, then the breakaway needs to go to the battery negative directly before the switch. The problem with that is where the negative is tied to the frame. If your breakaway uses the frame as its ground, then tying the breakaway negative to the battery negative before the switch will try to power anything else connected to the frame - regardless of whether the switch is on or off. I'd put the switch on the positive, but if your breakaway design used an isolated ground, it would be perfectly fine to run that ground before the switch and put the switch on the negative after that connection point.
A breakaway switch only switches the positive feed to the electric brakes. The brakes themselves are grounded and it is impossible for them to work in a breakaway situation if the battery ground is disconnected.
Electro-hydraulic brakes may be a different situation, I have no experience with them.
Some breakaway switches do have a ground connection but that is for an indicator light and has nothing to do with the braking function.
I already stated previously that the disconnect should be in the positive with the breakaway connected directly to the battery prior to the switch.
