You'll get a lot of smarter answers than mine from the other guys here... but my 2 cents is that, if your rig has an integrated 3-stage charger (bulk charge, absorb charge, then a trickle/float charger, plug it in and you're good to go. Just make sure the battery (s)' fluid level is good. Decent ventilation can't hurt, either.
I can't say if your chassis battery is integrated into the house charger (doubt it), but I've used simple 12v float chargers from Harbor Freight Tools (about $8) on my RV batts, my lawnmower batt, and cars (in a garage) and all the batts seem to love it.