We haven't tried any that are battery-powered. They've all needed connecting to the car - but you can get some models hardwired at Halfords so they don't need to be plugged in and wires won't be clearly visible. Some dash cams can run for 30 mins - 1 hour on battery power but dash cams aren't really designed to run off battery power, and those that say they do don't really have big enough batteries to be any use. Imagine recording a video on your phone for an entire commute, it would be completely dead by the end of your drive.