New owner

[Rpdanger]

2023 Thor tranquility works fine on shore power. Within seconds after separating from shore power, yellow lever pops out, no battery power. What am I doing wrong?

 

[Holdmybeer]

Before disconnecting try turning the inverter off, turn off items like the maxx air fan and lights, disconnect shore power, after 30 seconds if everything is okay, turn the inverter back on.
Also check for any loose terminals. An even slightly loose terminal creates resistance and heat which will trip the thermal breaker everytime the load shifts.

 

[TheLooks]

Check the voltage at the batteries with and without it plugged in. Convertor may be masking dead batteries.

 

[TheLooks]

Second to that is the convertor will power the unit even with the battery disconnect turned off. Maybe check that?