Some observations after a trip out west camping some nights. I have a bluetooth battery monitor installed so can keep an eye on voltage.
- Continually opening and closing doors (not the rear) wakes up the system and quickly draws down the battery.
- Reducing access through the passenger doors by unloading the vehicle and distributing stuff that needs ready access to the rear by the rear door with the vehicle locked. This reduced power consumption.
- After the first night opening and closing doors the voltage was about 12.2 volts. Waking it up lowered it from 12.2v to about 11.9v triggering a "Low Battery Warning". I was instructed to start the engine which I did. The engine ran while we had breakfast. This is the interesting bit: after 40 minutes the engine stopped of its own accord. The voltage was 12.75.
It's a nuisance for sure but not a deal breaker. Using the engine generator to charge the battery is a solution. Continually drawing the battery down to 50% SoC will reduce the life of the battery I guess.

