1) All radion devices are powered OFF in these cases:
- When master avionics switch is OFF
- When the Bus voltage is lower that needed for the device works
- When Bus is OFF or failed.
Just check this and you will see.
The default bus number for the radio devices is Bus #1
If you Battery switch is connects/disconnects some other bus you can select this bus number when assigning the display in the configurator (or "Edit" it if it is assigned).