Hi Guys, Over here in the UK we have a USB socket in the under seat compartment (Three Seat Model), I've only just done this, but I got hold of a 9ft long USB lead and I fed the cable from here to the Dash Cam in the centre of the upper windscreen, it takes it's power from the radio (5v) and sleeps when the vehicle is locked. Done this on my 2013 Mercedes C Class too, works a treat.
Be safe..
Dave