Upgrading an older motorhome battery system can be an opportunity to consider modern lithium technology. Lithium RV batteries from Epoch use LiFePO4 chemistry and are available in several capacities and voltage configurations. With roughly twice the usable capacity and about half the weight of lead-acid alternatives, they can provide more usable energy without a similarly heavy batter... https://www.epochbatteries.com/collections/rv-van-camper-lithium-batteries