This is a very common problem on the Edge 205 adn 305. Riding along and the unit shuts off for no apparent reason. Unit will turn back on and work normally. I install a hardware fix for this. It is a permanent fix, unlike using spacers and other poor advice out there on the internet.
This is a 350mAh battery. My testing shows training time up to 10+ hours in "training mode" a full day with "GPS on" and 2 weeks in power saver (time only) mode
Contact me before purchasing the Unlisted Repair Service to make sure I can and will repair your GPS.