[rohrmann]

Do not depend on that disconnect switch to fully remove load from the batteries. That switch only disconnects 12 volt power from the inside electric panel. For a full disconnect, either remove the ground cable from your batteries or install a disconnect switch in that ground cable, which will stop all power from the batteries. Regardless of whether you open the factory installed battery disconnect switch or install another disconnect switch at the batteries, you will not be able to charge the batteries with the converter when the batteries are not connected. With a disconnect switch open at the batteries, you also should not tow the trailer as the emergency brake switch would not be energized if the switch is activated when the cable is pulled.