I am a big fan of AGM batteries.
The charging voltages are the same as for any standard battery — no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. AGM batteries have no charge or discharge current limits. AGM batteries to deliver and absorb higher rates of amperage than other sealed batteries
AGMs have a very low self-discharge — from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than the usual lead acid batteries.
The AGM fast recharge means less generator time if you are boondocking.
I use a 60 amp Xantrex converter.
My batteries are Deka 12v size 27