One of my future project desires is to put in a 2 source power switch for the stereo so we can power it off either battery bank. I can see where each battery might have an advantage at certain times.
But this is an issue that has plagued both RVs and boats for years. There are two issues unique to RVs/Boats:
- They tend to be put into storage or are otherwise not used for significant periods of time.
- RV/Boat owners tend to want to power the stereos while not moving; i.e. at a campground or anchored in a cove.
Both of those situations seems to favor being powered by the house batteries. However, when the RV/Boat is in operation, its often desirable to power the stereo via the engine alternator/battery.
I have to admit, I have thought of some crazy schemes about this, including powering the keep-alive circuit with it's own dedicated battery, transfer switches, etc.
The only thing that works on a RV is the owner...