Forgot to mention - to dispel the fears of things going from worse to bad quickly, when something happens to charging system or battery. Yes, anything can happen. But...
The output of my charge controller is protected with DC breaker, and the ONLY Pos wire from the battery goes to all-trailer Pos bus via marine fuse mounted dcrectly on battery terminal. Trailer loads are wired to that Pos bus via their own DC breaker - consider this an "all-trailer Off switch". Anything happens to the charger - breaker will trip. Battery short (or any other short downstream) - fuse will blow.
