How to Add an Extra Battery to Your Nissan Maxima
- 1). Insert the battery tray into the trunk of the vehicle, just inside of the wheel well. Drill 1/8-inch holes through the battery tray and the trunk bottom. Secure the battery tray down with 1-inch self-tapping screws.
- 2). Disconnect both positive and negative battery cables from the existing battery. Cut the existing battery leads off with side cutters. Attach one end of the new red wire to the new battery lead and bundle it with the existing red battery wires. Crimp the end with a wire splicing tool. Attach one end of the new black wire to a new battery lead and bundle it with the existing black battery wires. Crimp the wires together.
- 3). Unroll the spooled wire until it reaches past the rear bumper of the vehicle. Run the wires underneath the vehicle. Drill a 1/2-inch hole in the bottom of the trunk for the insertion of the new battery wires.
- 4). Sheath both the new red and black battery wires together in a plastic wire covering. This will give the wires protection from the elements outside of the vehicle.
- 5). Cut the new wires off approximately 6 to 7 feet beyond the rear bumper of the vehicle. This will allow for enough wire to reach the new battery. Slide a rubber plug or grommet over the black and red wires together, then slide the plug on the wires, about 7 feet towards the front of the vehicle. Insert the wire ends into the 1/2-inch hole and feed them to the new battery.
- 6). Remove about 1 to 1-1/2 inches of sheathing off of the wires. Install the new battery lead ends on both red and black wires.
- 7). Press the rubber stopper into the 1/2-inch hole to seal the inside of the trunk.
- 8). Install the red and black wires onto the new battery in the trunk of your Maxima. Install the red and black wires back onto the existing battery under the hood. Tighten all terminal leads down with a ratchet and socket combination. Use only 10 to 15 foot-pounds of torque to tighten the battery leads and terminals.
- 9). Use plastic zip-ties to tie the loose battery wires to the frame of your vehicle. You can tie the battery wires up to existing brake lines as well.
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