Look around for a batteries plus, they carry rebranded East Penn/Deka batteries as Duracell RV/Marine deep cycle AGM, theyíre sealed units and can better withstand extreme temp changes and discharges without damage. Youíll want to match the size, if itís a big honker, most likely a 4D.
Youíll probably want to address the charger issue by getting a bigger charge unit, or get a charger/inverter unit so you donít keep running into the same issue.
I canít remember if you mentioned if you have solar or just the pre-wiring, add it if not, itís the best way to keep things topped off and your battery happy if your rig sits outside between trips.
'03 Ford E350 7.3L Diesel
(de)SMB'd Custom RB-50
Quigley 4X4 w/Deavers & Agile Offroad's R.I.P. package
CCV High Profile Pop Top