Start battery storage

[trucktramp]

It looks like it will be a while before I take the bus back out on the road so I need something to keep the start batteries up.  What is recommended?  I'm thinking along the lines of a "smart charger".  I just don't want to have to buy new start batteries because I let them go totally dead if I don't have to.

[eddiepotts]

I use a cheap walmart 12v smart charger. I disconnect the batteries then use a set of jumpercables to tie them together and walk away. It keeps both batteries hot with one charger.