Originally Posted by NorSnrub
I had 2 12v and one failed and drew the other down. I couldn't tell which one failed. I now have 2 6 v and had the same batteries in 2 different trailers for 3 yrs.
Couldn't agree more. I had 2 size 24 12V in parallel. For some reason, and unknown to me, the converter 30 amp fuses (to the battery) blew. In desperation, I put a 10 amp charger I had on the batteries - it would not handle both at once. So I recharged one battery at a time, but did not get them exactly equal, or one battery had failed (unknown to me).
When I hooked up the 6 gauge parallel wires, the wires promptly melted their insulation and glowed cherry red. The off-gasing of the lesser charged battery had flames at the glowing wires and at the vent at the battery cell cap. With electrician's pliers (gripped on the rubber coating) I cut the wires, which put the fire out.
I replaced with two 6 volt golf cart batteries from Costco ($150 for both). 116 AH available instead of 80AH from the 12V batteries, no risk from unequal battery charges. A lot less expensive than I expected. The batteries were a perfect fit for my existing battery box. And yes I added one of those marine shut-off switches to isolate batteries from camper when desired/needed.
Since our A-frame is set up for long weekends, and not extended stays, I feel much more confident with the golf cart 6 volt setup. I have more capacity, and easier to maintain. If for some unlikely reason one of the batteries dies, we go home earlier on the weekend - the same as if we ran out of propane or water.
Photos to follow.
2014 Rockwood A122
2008 Hyundai Entourage (minivan)
camping Colorado and adjacent states one weekend at a time
last trip - last weekend, 4 days in Lincoln, Nebraska