Our RV Adventures: Modification: Adding a Second House Battery

Recently, I completed a major modification to the RV. This modification is one that will greatly extend our camping time when there is no hook ups at the campground but still being able to enjoy some of the comforts of home. I added a second deep cycle house battery to the rig.

For this entry, I'm not gonna take you through step-by-step on how to add another battery; rather just show you the highlights of some of the challenges I faced and the solutions I came up with in completing this project. So, let's begin.

One of my first questions I had was, "Could I even put another battery on the trailer?" I have seen numerous other travel trailers have a second battery installed and some even came from the dealership that way. I figured that the area dedicated for batteries on a TT was standard and that they were suppose to be able to hold two. I was wrong and, of course, my RV was one of the special ones. The area on the frame dedicated to the batteries was not wide enough to hold two group 24 batteries in battery boxes. Take away the boxes, then two group 24 batteries would fit side-by-side. So what were some of my solutions?

After brainstorming with the wife on different solutions to mount two batteries on the TT we came up with three. One, was searching for a double battery box that would hold two group 24 deep cycle batteries side-by-side. That was impossible to find. There were battery boxes that would hold multiple batteries, however, not the size I was looking for. The second solution was to mount wider "rails" to the frame so two batteries, in individual boxes, could sit side-by-side with plenty of room. However not having the proper tools, like a welder, to attach the rails to the frame would make this solution extra difficult. So the third solution, which is the one I went with, came from another RVer online and it was his solution for the same problem. I decided to use a plastic tool box that was the same width as the area dedicated to the batteries. Two group 24 batteries could fit side-by-side and with a few modifications to the box, it could become a battery box easily.

The original setup from the dealership.

Removing the battery box and relocating the LP gas line, two Group 24 batteries will fit side-by-side.

Top down view of the batteries side-by-side

View from underneath of the new battery box trying to fit in the battery rack. Note the overhang. The battery box fits width ways but not depth.

View showing the lip of the front rail. Note that this side of the battery box fits in nicely.

The battery box. It's a DeWalt tool box. This one I have already started modifying by adding vents and cutting a groove on the bottom to accept the lip on the rear rail due to the overhang from the box.

View from the top down of one of the batteries in the box. Note the cardboard at the bottom to give the batteries enough lift inside the box.

The box installed in the battery frame. Both batteries fit side-by-side and they are wired in parallel in order to give longer amp hours without increasing voltage. Not only are they wired positive to positive and negative to negative, the positive wire from the RV is on one battery and the negative wire from the RV is to the other battery. This keeps the charges balanced between the two batteries.