TV Power Confusion

I can’t confirm which battery, although I would suspect the MH battery. The entertainment unit / sat nav in ours certainly does. Also the tracker. However, it will only flatten it if it isn’t being recharged. Ours charges either from mains (via battery charger) if hooked up, or  the solar panels if not. If you measure the voltage from the cab battery when you’ve been parked up a while it should establish what is happening. If it’s reading 13 plus volts it is being recharged,  if only 12.7 or less it’s not. You may have an inbuilt display that shows the state of charge for each battery, otherwise you could use a multi meter.

What is the make and model of your motorhome and your ‘can dash console’, by which I think you mean your radio head unit. Typically this will have the radio, sat nav and reversing camera screen maybe.