The device is useless because it discharges the battery within a few days to the extent that the car no longer starts. My battery has when fully charged 12.7 volt (Bosch) and is 3 years old.
The device is operated in the cigarette lighter and even if I with dashcam in the cigarette lighter
and radio and air conditioning off, the battery is completely discharged within a few days. Normally I always drive with radio and air conditioning, ( without dashcam) and never had a discharged battery,
so I can say that this device consumes more energy than air conditioning and radio together. I have now had to connect my battery to the mains for the third time and recharge it to start again within 2 weeks.