Inverter use

[WDH]

New to 5th wheel world
Still confused on when to use inverter
My 2021 has a on off switch inside
I know I don’t need to turn on when on shore power
Do I need to to turn on when towing?
I understand I need to turn on if boondocking
Mainly want to be able to keep residential fridge going when traveling

[Freedom@62]

We have been full time for a year now and on shore power with inverter off. Only cut it on when traveling and runs res fridge good. Truck helps keep batteries charged. We never boondock but understand it will run batteries down without solar or generator but will keep it running 8 hrs or so based on usage.