battery box photos
Here are photos of what I did. The aluminum C channel was something I had. I mitered the corners and put small L brackets inside the channel for stiffness, then attached it to the top of the battery box with sheet metal screws (or pop rivets) then attached the original top of the box to the new frame. I had some blue plastic matting which I simply put over the battery tops for slightly more protection.
The batteries are 6 volt golf cart type from Costco, about $90 each. They have the same footprint as the original type 24 that were in the trailer on delivery, but are about 1.5 inches higher.
At the top of the photo you can see the + cables, two large ones, one for the inverter, one for the main power. The orange wire goes to the electric jack. The blue wire and small white fuse is for the Tri Metric power monitor. The red and black jumper wires were the original ones used to parallel the original batteries.
The bottom of the photo shows the 100 amp shunt mounted on it's side with a short piece of twisted copper to connect to the negative side of the battery. The gray taped wires are part of the Tri Metric monitoring system. They carry virtually no current and are thus pretty small in size. I think I have a 1 amp fuse in the white fuse holder.
The two large black wires are the negatives for the main power and the inverter. One was a bit short, and that is why it runs across the battery at an angle. I would have liked 2" more cable, but it was not available and I didn't wish to extend the wire with a splice.
The battery hold down was extended with a piece of all thread.
When I disconnect the batteries for the winter, I simply remove the center red and black connecting wires, quick and simple. I don't have to mess with the shunt or positive cables that way. I leave the batteries in place all winter. They take very little charge in the spring when I return.