You are correct, AGM Lead acid batters are the best bang for the dollar, I run 6 - 6volt golf cart batteries running my 30ft 5th wheel.... Correction if one doesn't drain there AGM bellow 20% you can get 5-8yrs out of them. my batteries never drain below 12.2V and that's after 5 days of use. Fully charged is 13.42V then recharge them with a 4stages charger.