Roger,

I hard wired in a marine battery charger (water resistant) for the bus batteries as they died on me once. (Had a bus full of kids getting ready to see xmas lights - bummer). My fault as I was playing a lot with the lights, (kid with a new toy syndrome) and killed the batteries. I put in a three stage charger that can stay on full time and not cook the batteries. About $150 - heading down to the bus barn so I'll get the model number for you. I just mounted on the bulk head next to the bus batteries and plugged into the outlet for the crankcase heater. Works great.

Mike