Couldn't you use a standard cigarette plug adapter?? This would supply power as well as ground.. just like the inside of the vehicle. This way, just unplug it and be gone... You could also run it from the cigarette plug down the frame to the rear where the cooler is and put a quick disconnect to make it easier and faster.. Just a thought..
The center is the positive and the side is the ground on the cigarette plug.
The center is the positive and the side is the ground on the cigarette plug.