In the van I know whats using what, when and how much, well roughly, Big Mal doesn't have anything running unless its turned on by a proper switch, the diesel heater has a main power switch, the TV/STB's/Mobile broadband units all have a master switch for each of them along with other bits , if it didn't have a switch originally it has now, nothing on standby.... Dont forget to turn the AC off at the switch, it has a 12v circuit usually.....
Thats why I don't like all these techo things, screens, blutooth etc they chew power, the blutooth on your phone chews power not a drama when plugged into a power station but big waste when off grid, some even leave their chargers/Invertors and gear on, no wonder they need 800w on roof and 900ah in storage.
I hate outside stereos, mainly because the rest of us like to listen to our own music and some have a need to share ........... I find some good old C&W sorts them out.......... or a bit of Slade Alive............. sometimes even Blu Grass...oh yeah!!!!!!!