Charging edge 25 while riding and recording

I have found discussions about other Garmins being charged while riding and recording. Has anyone here had experience using their edge 25 on long rides that require an external battery? What set up do you use to mount the unit when plugged in? (tape, elastics etc) If you unplug it in the middle of recording, will it reset? My Edge 25 never lasts longer than 7 hours and so I need an external charging solution that hopefully won't require multiple files.