You can get battery powered units that run even when your engine is off. I've got a Transcend DrivePro 200 which is great for the money.
I now shout "dashcam buddies!" to any car I see with a dashcam.
I have lots of those 6 cell battery banks..
But wouldn't 24 hour recording put alot of stress on the camera/ sd- cards ?
What are yous guys's thought on Active cooling.. I could easily cut a hole in the back of the camera and put a fan in there. or even duct one with some cardboard.