Keeping batteries charged while not in use?

I have a 1998 Class C and changed out the old single stage converter to a Progressive Dynamics three stage converter. I also installed an Amp-L-Start in the engine compartment. When the Progressive Dynamics is on, it charges the chassis battery also though the Amp-L-Start. When camping and you are using the Converter, and turn on the dashboard radio, the current it draws, comes from the converter through the Amp-L-Start and your chassis battery stays charged. Works very well. I leave my RV in the garage plugged in all the time. When the charge goes into maintenance the LED lets you know with a slow flash every few seconds.