Outer Limits 4x4 Board

Hi there people I am fitting a battery isolater and am not sure whether to isolate the positive or negative cable can some one please help me

isolate the positive.

most cars i guess would isolate the positive but alot of our machines at work that run alot of computer equipment we isolate the negative side

Without drawing a diagram to check, I suspect that if you isolate the negative, you'll need to wire all accessories direct to the "isolated" battery - using the chassis as a return path will effectively bypass the isolator. So, if you do this, I guess you would want to isolate your main battery, and then everything else (including standard vehicle accessories, like lights?) should drain the aux battery. I think.

Would it not depend on whether the vehicle is positive or negative earth??

stuee wrote:Would it not depend on whether the vehicle is positive or negative earth??

Well, yes, I was presuming a negative earth.