When my LMTV was shipped to me it had two car batteries thrown in to get it started an onto the semi. It wouldn’t turn over to get it off the semi without a jump start and to work with the original batteries (BLEM 6TL) would run me $250 each for four and were special order… on the road this wasn’t going to do.
After talking with some friends and taking some measurements I found that not only could I fit more group 31’s in the space allotted I could get them almost anywhere for about $80 each. Here are the specs on the Group 31’s: Cranking amps 1185, Cold Cranking 950, Reserve 195
Now in theory, this fits, and I have the top 4 so far but here is the issue. The portion where the top of the battery box clips in is obstructed by the batteries themselves so I had to make some additional space to push the batteries forward. So now that you know what I’m up against and where I am, I’ll get to the install.
I had to start be removing the bottom portion of the battery box to allow for more height and there were awkward tabs for the original BLEM batteries that just had to be removed to make this work. I used a die grinder to cut the stainless hardware so I didn’t have to take apart the entire air assembly and brackets.
discarded battery tray
This lead to a new problem, there were additional tabs under this tray that needed to be smoothed out for the new group 31’s. I created a template for the new base using some cardboard then I cut 1/2″ thick UHMW for a tight fit around the tabs and I eventually had a flat surface. Unfortunately this stuff only comes is white.
Template for UHMW
Below is an older photo, but I had to reroute the wire coming out of the switch box to the back of the switch box so that I could bend the existing wire around the batteries. This was one of the few wires I didn’t replace but I plan to.
New UHMW base
Replace your wiring with welding cable, it allows for more surface area which is good when it comes to electrical current and its much more flexible. I can’t tell you how long I fought with this before I decided to make my own wires to work.
I cut some holes in the top of the box that used to help hold the batteries in place. I circled back and used G/flex epoxy adhesive by West System. I used a black pigment with the epoxy to get the color match. I’ll eventually spray this with a bed-liner material.
EDIT: I crimped all my wires but in the future I plan on doing something like this to ensure a better connection and seal.