Hello Robert,
When a coach is sitting there is a continued draw on your batteries from the CO2 Detector, Propane Detector, Internal Clock on the Radio, and possibly even the Booster on the TV Antenna.
By turning off the 2 battery switches and the Inverter Switch, you are stopping any current draw and saving your batteries.
You may also want to check the water level in you batteries to ensure they are topped up.
We had an issue with a 2 year old CO2 Detector going off. During a service visit to Fleetwood in Decatur, their Tech stated that a specific model was no longer being used because of issues.
A new hard wired detector solved my problem.