[Richard]

The scenario I am imagining is that when the Xfer switch cycles, it briefly interrupts power to the inverter/charger. When the charger comes back on, it goes into bulk charge mode. But this is only in my imagination. And the echo charger would have to then pass the higher voltage from the bulk charge to the chassis batteries.

And the isolator should not allow the banks to talk to one another, because it is in practicality two great big diodes.

And you said merge switch is off.