Before we start talking about the installation process, there are some simple truths we want to cover that prove lithium batteries are good for RVs. There's a lot of information floating around and many different versions of lithium-ion batteries in the marketplace. Unfortunately, many people can't talk about these. You need to know some other simple truths to determine the lithium battery size you need for your travel trailer or motorhome. Most RVs on the road today use Group 27 batteries. Some of the Classic Era(1971-1989) or. YES, 30-amp RVs can use lithium batteries. RV manufacturers install two 6-volt batteries as a precaution. If one goes bad, there's another in. To determine how many lithium-ion batteries you need for your RV, you have to think about your electrical needs. Every electronic device requires a certain amount of watts/amp. Most RVers want to know how to increase the capacity of their RV batteries. It's been hard to find a campsite during the Remote Period of the Modern Era's(2020- Present) RV boom. Dry camping has become a substitute for.