Installing a Dual Battery on a Truck Camper

Jeff Johnston: Many RVs come with one battery, but owners often add a second battery to extend off-grid camping time and power reliability. We definitely needed a second battery in our Palomino and we started with the factory option second battery tray. The project as outlined and as we started it falls in the best laid plans category. 

To finish up the electrical part of our Palomino camper setup, we’re going with the double battery system. Now the optional battery tray, the second tray for the Palomino is on the outside of the body, which means the battery’s exposed to the open air. For that reason, we decided not to go with lithiums because lithium batteries still have problems when it gets down around freezing or colder. 

AGM batteries are a lot better suited for exposure to cold climates. We decided to use the Sun Cycle AGM or absorb glass Mat batteries from Go Power because they serve well with the complete Go Power solar charging system we already installed in our Palomino. And these are made and designed for basically, solar use as well as other purposes but for solar charging, these guys work great. 

Now these are rated at 24 amp hour capacity which is terrific, that’s a lot of power. When you’re using a pair of 12 volt batteries to get a dual battery system, you hook ’em up parallel and you’ve got your 12 volts. In this case, we’re working with six volt batteries. So the positive on one 6-volt battery goes to the camper, the negative on that battery goes to the positive on the second battery, and the negative on the second battery also goes to the camper. The net result is 12 volts at a really nice amp hour rating. Palomino’s optional second battery tray fits outside the camper, but it wasn’t going to fit. 

Once in place, we measured again compared to the Ram truck bed and found it was just too tight a space. We opted to fit both batteries inside the interior utility compartment. The original battery was positioned sideways in a vented enclosure, which we didn’t need for the new sealed AGM batteries. We installed some floor strips to keep the batteries from sliding around. The helpful crew at AM Solar in Springfield, Oregon helped us with trimming the big cables to size and installing the crimp on terminals. Working with this large cable can be tricky. It was a snug fit, but the AGMs both fit in the compartment mounted front to back. The wiring still needs to be cleaned up but everything works and the setup provides more than enough power for our modest needs. A second battery may be just right for your RV as well. It’s a good investment.