Battery Disconnect Switch
Phantom electrical loads (small electrical draws) from several items in the typical RV, may lead to a discharged battery when the RV is stored for an extended length of time. Even with everything shut off, things like propane detectors, radio and tv memories or other devices do consume a small amount of daily battery current.
These will draw down the battery if the unit is not plugged into shore power. A battery disconnect switch can be used when the RV is stored.
Battery Post style of disconnect device - This type required that you physically unscrew the knob to separate the terminals - not the most convenient method but effective and easy to install.
This battery Disconnect switch is installed inside the RV where it is protected from tampering and the elements. Somewhat harder to install as you need access to the main wire from the battery that supplies the RV with 12 volt power.
There is a simpler version of the knife switch that clamps onto your battery post and then you attach the trailer leads to that.
Or there are more elaborate systems with relays and more wiring where you simply hit a switch inside the coach to kill all battery power.