Preparation
Connect the stripped ends to the new terminals on one end and to the ring terminals on the other end. Place the new terminals on the positive and negative posts of the new battery. Take the end with the ring terminals and connect them to the old battery, making sure to connect positive to positive and negative to negative. But no matter where you choose to install the extra battery, make sure that you have enough wire to reach it.
Materials
You will need a battery of a least 12 volts, two lengths of copper wire of about 3- or 4-gauge thickness and long enough to reach from the new battery terminals to the existing battery and new terminals. You will need two regular battery terminals and two ring terminals. You'll also need wire strippers and a crescent wrench.
Connection
Strip both ends of both wires about 1 inch.Decide where you Testament lay the extra battery. It could be in the engine bay, but there is not usually enough space there. It could also be in the cab of the vehicle itself, which also poses the problem of space, plus it can be unsightly and dirty. The third option is to install it in the trunk area.
