Bigger MHs use a latching relay operated by a switch at the entry which sends a signal to the latching relay to connect or disconnect the batteries. My Axis, a smaller MH with the batteries underneath the steps, uses a physical switch, a Perko I believe.
Based on my Axis experience the switch only disconnects the power to the converter and the appliances powered from the converter. It does not disconnect the cable from the batteries to the chassis alternator. This lets the chassis alternator charge the battery whether the switch is on or off.
But in your scenario, there are no sources of DC power at the converter since there is no shore or generator power and the batteries are disconnected, so there should be no voltage there either.
David
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