Battery Wiring

Ground Wire for front mounted battery

It is critical to have a very good chassis connection on the battery. If you don't do this the chassis can get power through the engine and transmission bearings, causing electronics in the car to have intermittent or fluctuating voltage.

My trunk mounted battery:

Prior to clamping ALL bolted or clamped connections (except solder points) are cleaned and given a light coating of clear silicon dielectric grease.

Battery hot wire is 2/0 welding cable, 15 feet long, and runs directly to the starter relay battery post on the starter. The lug at the starter, since exposed to water, is soldered on. The old heavy starter feed wire from starter relay back feeds electrical system.

Battery ground straps are 3/4 wide by 1/16th inch thick tinned strap with carry current rating of 150 amperes. Two equal length in parallel. These straps will act as a fuse if the welding cable would ever short to the chassis. The bottom lug is crimped and soldered. The battery post connection only crushed. Some sort of reliable fusing is mandatory for fire protection. The fuse links must melt before the 2/0 welding cable or battery significantly heats or melts.

Battery box homemade. Cut, bent, and welded here by me after an unsuccessful job by a local welder. This box is water tight aluminum, held down by six 1/4-20 stainless screws. The stainless screws with star washers sandwiching the chassis hold the box, and also provide the ground. A sealed plastic box fits over the battery and vents outside the car to a low pressure area. This prevents hydrogen gas accumulation in the trunk.

The battery is a large heavy Marine deep cycle battery. It is mounted on the right tire side, as high as possible, and back as far as possible to place maximum weight on the right rear tire. This caused a significant increase in traction with the street radial tires. This lead-acid deep cycle battery was selected because it has a very low internal resistance, and it won't fail as quickly if ever allowed to drop below 12.6 volts.

This is the not-so-pretty area that was under the old battery holder. It is not cleaned up yet. I cut the old battery negative lead and added a good high current clamp for the ground connection. The actual body connection is through a 5/16 stainless bolt with external tooth star washers on the bolt head and under a clamping nut. A second nut with spring or split ring lock washer and stainless flat washers holds and buffers the copper clamp, preventing direct contact with the steel car body. This areas was cleaned, tinned, and coated with dielectric grease before bolting.

More later..............