Review on TOPDC 4 Gauge Negative Starter Conductor: Optimize Your Vehicle's Power Distribution! by Brian Douglas

I bought this to install a battery isolator switch on a caravan. I put it between the negative battery post and the switch, then the original wire from the switch to ground on the frame. Now when I unplug the breaker I installed on top of my battery box, my battery doesn't discharge. Prevents "phantom" loads from draining the battery when not in use.