[JRTJH]

Most of the "newer" chargers have a trickle charge feature, however, when initially turned on, they charge at an increased rate for a period of time, then lower the charge to finish the battery charging cycle, then revert to trickle charge. While, in theory, putting that type of charger on a timer may sound like a "work around" I think you may find that when the power initially comes on after the timer has cycled, the converter goes immediately to increased charge condition and must cycle through its "process". If so, that may very well negate any benefit the timer may have created.

My suggestion would be to remove the battery, take it inside and put it on a trickle charger or just store it in the corner of the garage and connect it for a couple of hours every month or so.

If you're like me, I tend to forget, so I just hook my charger up the first of every month and disconnect it the next day.

If you want to leave your RV hooked up to 110VAC through the winter, maybe you could just flip the circuit breaker for the converter (also remove the battery) that way you're not powering the transformer and rectifier in it all winter long.