battery relocation

Mount: I first tried to custom mount a Summit Racing aluminum battery box (shown above) in the same location as the Ruslow mount pictured to the right. It's just too tight for comfort.

I then decided to suck it up and get an Optima red top (part #34/76). It is much more compact than the stock Group 27-sized battery and weighs a few pounds less. As luck would have it, the side panels from the Summit box fit like a glove. In the image below, one of the side panels has been drilled to act as a bottom plate. The grommets are just to hold the top of the battery in place. The top grommets are those supplied with the Summit box. The bottom washers are some neoprene washers I had laying around.

The bolts supplied with the Summit box inserted in the holes marked with the yellow circles allow four additional clamping spots top and bottom. The battery is very secure. Additionally, the 5/8" rods are placed in such that the battery cannot slide out in any direction.

I could not find 5/8" bolts threaded all the way to the head, so I bought 5/8" thread-all and 3/4" OD steel tubing to act as sleeves. The coupling nuts are just in the photo for temporary use as a locating point. The battery is installed with 5/8" bolts through the bed. The hardware sequence is:

5/8" bolt
fender washer
bed
fender washer
lock washer
coupling nut
lock washer
5/8" all-thread
top plate
battery
bottom plate
lock nut

The thread-all is covered with spacer sleeves made from 3/4" OD steel tubing to maintain the proper height between the top and bottom plates. All holes were drilled with a Unibit, one of the greatest tools ever invented. The coupling nuts are attached to the thread-all with 1/8" by 3/4" roll pins.

Here is the finished box, ready for installation:

box installation:

Proper securing of the battery is critical. Even a relocation to sanctioning body specs can break free if the collision is violent enough, turning the battery into a 50 pound projectile. For under-the-bed mounting, the concern is slightly less than for in-the-bed mounting.

The forces that a battery under the bed will be subjected to in the event of a collision are immense. Make sure to weld reinforcements or use fender washers if sheet metal is the mounting surface. I used large fender washers on the top only, figuring that if the force is strong enough to pull 3" washers through sheet metal, the truck is probably totalled anyway.

Here is the finished product. Note that I used a side-to-side rather than front-to-back arrangement. With the smaller Optima battery, it just fit perfectly between the bed reinforcement rails. This arrangement would not seem possible with the stock battery (compare with the Ruslow mount above).

This photo shows the location of the bolt holes:

Two of the washers had to be cut to conform to the bed.

Box fabrication time was 5-6 hours. Installation time, including running the 0-gauge cable to the engine compartment and the master disconnect, was about 8 hours. While relocating the battery can improve the front/rear weight distribution a full percentage point, unless you are really serious about your truck (or need the underhood space for a cooler or intercooler fluid reservoir), I don't think the time would be worth it.

Martin came up with a more elegant solution using a $25 Taylor pre-built battery box.