Garmin RCT715 external battery

I just bought a rct715, but the battery life, according to DCR is too short for some of the rides I’ll be doing. Has anyone tried using an external battery with it? More specifically can I use the edge external battery with it?

Just tested by plugging it in to an external portable charger (using the Garmin cable) and I am able to get it to charge while still working as a Radar and a light. Not sure about the camera or your model though, mine is an RTL510.