I have a 2017 MB Sprinter chassis with a 2018 Thor Siesta mh. I used to have a 2016 Winnebago ERA on a Sprinter Chassis before. Each time I had chassis battery issues. If the chassis battery gets too low or dead, the ignition key will not turn. I then bought a small solar battery tender system for about $25.00. Each time I store the mh, I plug in the solar battery tender under the hood to the red battery jumper and the ground. I then run the wires through the front driver's door and place the solar panel in the windshield locking the door before leaving. I also had my dealer install an emergency house battery to chassis battery switch so I can actually jump start it from the house batteries. I never have a chassis battery issue now. I just have to push a dash button to activate the connection.
The emergency jump from house to chassis battery, sounds interesting. I have had no issues with mine, and I do always carry a couple of chargers, so I could always get started, even if I had to run the generator for 120 volts to plug the charger into, if one of my inverter powered outlets wouldn't be enough. Batteries are always a PITA.