The second spin off from the solar panel install was a new battery box.
When I picked up the T-105′s I was disappointed with the selection of boxes to hold 6 volt batteries. Part of this stems from the fact that the batteries are connected in series in a typical RV application, so they need to be connected to each other. This requires they are close together so most of the boxes on the market are built to hold 2 batteries side by side. These boxes were, well, boxes. They were “functional” but pretty ugly and they were going to require some modification of the rails hold my existing batteries in order to make them work. I also knew that I might eventually need 4 batteries for my system. I thought about getting a truck storage box but I was going to have to hack it up to make it work for batteries. These also aren’t cheap. I thought if I was going to have to spend a couple of hundred bucks for a box, I could build one for that price, and I could make it EXACTLY how I wanted.
And so the custom battery box was born…..
I am actually pretty lucky that I have as much room as I do on the frame of the North Trail. Some trailers just don’t have room for batteries, let alone 4 of them. I don’t think much thought goes into that at the design meetings, because most people want hookups when they camp. Battery placement is not high on the priority list. Perhaps it was inadvertent, but the design guys at Heartland left plenty of room on the front of the North Trail.
Originally the 12 volt battery my trailer came with was mounted in channel created by 2 pieces of angle iron. The T-105 is pretty much the same footprint as a 12 volt, except it is a bit taller. Because I was planning to have 4 batteries I turned them sideways so they would all fit within the width of the frame. I did remove the angle iron channel, and the metal supports that make up the spare tire storage served as the mounting points for the new box.
Above is a shot of the project mid construction during a dry fit. I built the box entirely out of 16 gauge (1/16″ thick) metal. I had the individual pieces cut at a shop I use and then had it welded together. The latches are your basic tool box latch that can be locked. I tacked these on instead of using bolts. For the vents I got a plastic vent (white in the picture) at a local RV parts store. It is a vent typically used in RV’s where the battery box is vented by hose to the outside. I placed a vent on either side of the box and it gets good cross air flow.
Since I only have 2 of the 4 batteries right now, I placed a couple of dividers in the box to keep the 2 batteries centered and prevent them from tipping. Having them side by side also allows for easy connection of the wire that connects from the positive side of one battery to the negative of the other. Wiring the batteries in this way produces the required 12 volts from the 2 – 6 volt batteries.
I replaced both the negative and positive battery cables as part of this project. The ones on the trailer were too short and they were already pretty damaged from the sun. Because my box is a trapezoid shape, I have 2 triangle areas on either side that will be empty even when I have 4 batteries installed. I used this area as the place for my cables to enter the box. I used a plastic strain relief connector like I used on the junction box that will keep water out and prevent the cable from getting cut on the metal. For paint I did it myself with standard metal primer and black paint.
This what the finished install looks like. I don’t think it looks out of place on the trailer, but yet this is totally custom. Overall I spent about $140.00, and $80.00 of that was having the lid cut and bent. I could not have bought anything for this amount that would have held 4 batteries and fit the trailer as well as this does. It also doesn’t add much weight, which is important when each battery weighs 62 lbs. 
