Add a switch. Too many gizmos to remember to turn off. Wire the switch on the negative, the ground side to avoid shorts. No wire but a single wire from the cutoff switch should be connected to the battery. Connecting a Harbor Fright 10 amp mechanical charger will top your house batteries off 10 times faster than the rig's converter. Disconnect the negative cable clamp from the ENGINE battery only if by doing so it does not force you to return to the dealer to have the computer re-set. If you do not know the answer, then check with the dealer or on this forum. A fifty dollar solar trickle charger for the engine battery beats a 100 dollar trip to the dealer every time.