Chassis battery

Since 2011, Winnebago has used a "BIM" (Battery Isolation Manager P/N 174291-01-000) device to monitor both battery systems and operate a solenoid as needed to maintain the charge on both systems. The BIM replaced the older generation "BIRD" (Bi-directional Isolator Relay Delay) that had an annoying loud solenoid. It looks like your BIM may have failed in some fashion.

On my Chateau 28Z, the shore power charger is disconnected from the batteries (both house and chassis) when the battery disconnect is set to "store". You can check with a volt meter across the house batteries; when the battery disconnect switch is in store, you would show a voltage of ~12.3 and a voltage between than 12.7 and 14.2 with the disconnect switch in "Use" (or connected...) and on shore power. If voltage is the same regardless and below 12.5, then check the fuses and breakers. Hopefully the solution is that simple.

One other note; the CO and propane detector and one radio draw power at about 1/2 amp from the house batteries whenever the switch is connected. Neither can be turned off independently.

I did two things to address this problem: 1) I replaced the original flooded battery (the factory tag was still on it) with an AGM; 2) I bought a Coleman smart charger from Newegg on a flash sale for $14, and I keep it attached to the battery while my rig is stored. I also keep a lanyard on the steering wheel to remind myself not to start the engine with the charger attached, lest I fry yet another battery charger.
HTH

We have the same model as yours, just called an Itasca. Ours and likely yours has the equivalent of a trickle start installed at the factory. It keeps both batteries topped up when plugged in. I don’t recall exactly what it is called, but it does the same thing. If yours does not do this maybe it is broke.

Kemer,

It didn't used to happen?
What have you added? A CO or LP monitor that should have been on the house bank?
No?

You have probably left on a light in a closed compartment or maybe a small fan somewhere. Just keep looking and you will find it.

Matt

+1 for Trik-L-Start

Ok, Many RVs the house converter or charger also charges the chassis battery.. Same as the Engine alternator charges both chassis and house via the isolator.

However MANY =NOT= ALL. yours may be one of the "Rest" as it were

IF you are supposed to have a bi-Directional isolator.. IT's not working

IF you do not.. Trick-L-Start

Do you have a volt meter that you can check the battery voltage.