All dash cams will come with a car power cable that uses the 12V cigarette lighter to power the camera. This cable will provide power while the car is turned on but will power off the dash cam when the car is turned off.

Most manufacturers also offer a hardwiring kit which will plug into the car's fuse box and allows additional dash cam functionality. If you are wanting a dash cam with the Parking Mode feature, you will also need to pick up the hardwiring kit along with your dash cam purchase. Using the hardwiring kit allows the dash cam to pull power from the 12V car battery even when the car is turned off. To make sure you don't run your battery too low while away from your vehicle, these hardwiring kits will also come with a low-voltage shutoff that will cut power to the dash cam if your vehicle battery happens to drain past a good charge level.
