The success of my suggestion depends on if the chassis and house batteries being located next to each other. Make a jumper cable long enough to go from the coach battery terminal (where the coach charger connects too) to the positive terminal of the chassis battery (if more than one, it doesn't matter which battery you choose). If you leave your coach plugged into shore power the jumper cable will charge the chassis batteries as the coach batteries are charged by the coach charger or your battery minder.
Place a reminder to yourself to disconnect the jumper cable before using the coach.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
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