I caught a disaster fixing to happen on my Cushman 72 volt cart not long ago. Sulfur smells alerted me. Batteries swelled up and hot. On board charger, similar to my boat. Since then, I don't keep nothing hooked up to a charging system, auto or not. Plug them in when I need them, or know something is about to happen, hurricane's, etc. If a sudden event happens, I've got the resources to jump-off the system.

I know that they're are several companies that sell auto charging units, Minnkota, etc. But, their components are made by various manufacturer's. They just put them together. Better safe than sorry is the way I roll, even if it takes more effort.