Hiya! For sure, here ya go:
Check and see what your currently-installed original charger is rated at (amps) --- since your van was wired for that amperage range to begin with, you'll probably want to stay in the same amperage range with a new charger.
My Sportsmobile's originally-installed "Todd Engineering" Charger was a 30A unit, so I decided to stay in that same exact range and go with a new Progressive Dynamics 30-amp charger, model number 9130. I also added their "Charge Wizard" gizmo to it, which enables three (or maybe even four) stage charging. (This is an absolute must-do, in almost everyone's opinion, to get the most longevity out of your house batteries.)
Progressive Dynamics 9130:
"Charge Wizard" attachment (model number PD9105) for the 9130:
I dropped in a brand-new Exide Nautilus Group 27 (Lead-Acid Deep-Cycle) and have been very happy with it. Another buddy uses these in his SMB and he recommended them, I've found em to hold charge great and have a very respectable amp-hour rating.
Pretty sure it's the "Exide 27MDC."
(**It's possible I have a group 31....can't remember at the moment....that would be the "31MDC."