i see. in my daily driver, i have had luck using this
OBD power cable for parking mode. the very important caveat is that it states that it will cutoff power at 11.6v which is way too low to restart a vehicle. i have a bigger battery and it gets driven often so it’s always recharged. i have left it for an entire weekend without it hitting the low voltage cutoff but your application may be very different. nonetheless, i still carry an emergency starter battery in the hatch just in case my vehicle fails to start.