Go to the sites on page one I listed and you can learn all about lithium battery issues and benefits. Things like having volt start that will run the AC of the lithium and when they get low it will automatically start the van to recharge the battery. Pretty nice feature if you have a pet and want to leave it in the RV for most of the day. Also that you can use the sun to quickly charge the batteries to power the fridge, etc. I have one in my RV and run my fridge on it for a couple of days. Also check out Etreks/Ecotreks. I think it is the future of RV comfort, but like the old bag cell phones there are some growing pains to get thru. On the two sites I listed there are often RVs for sale that might fit your needs.