Hi Bert! It is always advisable to have your car camera to be set to "always-on" such there will be video evidence accessible for your insurance claims.

https://www.motorist.sg/article/487/the-importance-of-owning-a-car-camera-in-singapore#

If your car camera is connected to your cigarette adapter on a car that shuts the power off to the cigarette port when the ignition is all the way off and the key is out then it will not drain the battery of your car.

However, if the cigarette adapter port has “always-on” power and does not lose power when your car is fully off, then the car camera will continue to be powered as it has a source of power and this may drain your car battery.

Source: https://dashcameras.net/