Keeping Batteries Charged During Storage

Since we wouldn't be using our Class A year round (once we actually get one), especially Dec-Feb, how are the batteries maintained during storage? Is there something built into the coach to keep them charged? Or would I just need to keep it plugged in to my garage 50amp receptacle for charging?

With our Fifth Wheel, I just use a trickle charger, but I only have one to worry about.

John