Apu and Optimised Idle Battery question

I listen to radio at night with truck off to blockout outside noise, mines a 16 Cascadia, always starts, radio don’t pull much fire, but I know I’ve got good batteries not a weak one too

 

Not sure about Freightliners, but my Volvo will shut all non essential things, like radio, bunk heater, 12 volt outlets, cab lights, etc.. when the battery voltage gets too low. It's an attempt to preserve enough battery to start the engine. So far, it has always worked. Only time I couldn't start it was yesterday morning due to 2 bad batteries.

 

Opti idle sucks... better to turn it off.