My Palazzo has a trombetta relay/solenoid in the compartment with the inverter box. This relay connects the chassis and house battery bank circuits s together after a 1 minute delay. Mine went bad and 1)did not allow shore power to charge the chassis battery;
2)did not allow the chassis alternator to charge the house batteries while underway. I replaced the relay and that solved the charging problem. However that does not explain why your chassis battery is losing its charge so quickly.
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