No matter how many batteries you add, if you don't have an efficient way to charge them quickly, your problem will persist. The converter/charger in your motor home is probably a single stage and would take many hours to recharge batteries, especially if under sized. About 400 watts of solar power and a new converter and 4 new GC2 batteries should get you going in the right direction. The auto generator start is a nice option. We have a Big Buddy heater, but don't use it at night. It doesn't make CO, but does deplete O2. You can buy 100 watt solar panels now for $130ea. A charge controller will be another $160. Wire will probably add another $200. So for about $900 and DIY install you would have a good solar charging system.
