After a few weeks of delay, I finally got around to completing our battery upgrade project. That means we now have four 6V GC2 batteries wired up, two sets of two in series, in parallel, to provide 12V service to the RV from true deep cycle batteries. We chose NAPA 8144 batteries because they’re well regarded and easy to come by. The first two I bought a month ago cost $150/ea, but the two I purchased yesterday were $130/ea. No mention of them being on sale…
I found that the factory battery tray, which was originally populated with a single group 27 12V battery, worked perfectly for two of these side by side. I installed a watering kit for ease of maintenance and wired them in series.
I found a NOCO brand battery box on Amazon that I mounted in the cargo area on the other side of the wall, and dropped the additional batteries into it. Wired them up in series as well, with a watering kit, then connected them to the other battery pair and converted the it to a sealed box with a vent.
While not perfectly air tight, I taped over all the seams of the box with Gorilla tape and added a 1-3/4″ vent tube into the open compartment where the other batteries are. I used silicone adhesive to attach and seal the vent tube. The tube you see in the foreground is for topping off the battery cells with water.
After the batteries were installed and wired up, and I verified that they were actually providing the correct voltage with a multimeter, I replaced the Xantrex XM-1000 1000w MSW with an AIMS PWRIX200012SUL 2000w PSW inverter. The conduit fittings it came with were junk so I moved the ones from the Xantrex over to it.
Last, I upgraded the converter to a Boondocker 1275CL which supports the GC2 batteries I installed. The OE WFCO inverter that came with the RV does not provide enough voltage for bulk charging (if it even ever goes into bulk charge mode, as far as I have seen it will not). I verified the inverter worked then applied shoe power to the rig and verified everything is functioning properly.
After all these upgrades we have 460ah of battery capacity (230ah at 50% discharge) compared to the 85ah (42.5ah at 50% discharge) battery we replaced. That should provide us with five and a half times as much battery capacity and the ability to run without the generator or shore power for the better part of a day as long as we aren’t running heat or AC. Also, the GC2 batteries will stand up to a lot more abuse (frequent/deeper discharges) than the group 27, the new converter will charge them quicker and require less generator run time to charge, and the new inverter will power the entire circuit without going into an overload fault mode and having to be reset all the time. These batteries weigh about 64lbs/ea, so do cut quite a bit into cargo capacity of the rig.