Jerry Hensler uses the 8 D cells and claims that that setup will run a whole season off of one set of batteries.
His logic is its a lot easier to find some extra D cells in time of emergency than other types of batteries or to just replace a set if you forget or cant charge the acid battery.
Personally I have a 110 plug built into my jeep and I just plug mine into that.
Otherwise I use one of those booster jumper batteries that have a 110 plug built into it.
I can just plug the unit in to recharge it and its all self contained along with the fact I can still use it for a jump if I ever need to.