By the way-the AGM battery is exactly what a sometime user should use. AGM batteries have a very low discharge rate and can be charged very fast as long as you don't over volt them. Good Luck, TomC
I don't use my bus all that often and I finally put in group 31 AGM starting batteries in 2010 after losing two sets of starting batteries over three or four years. I still have to keep a Battery Tender on them or they will go dead due to parasitic draws from the DDEC and other things. They do seem to stay up longer when I am not on battery charger.
If I was doing it over again I would probably just have one bank of batteries for starting and house batteries. I considered moving my house batteries down where the start batteries are last year, but the compartment was an inch or two too small for my house batteries.