Edge 830 won't power off

Yesterday I charged the Edge to 100% at work.  I came home from a 10km ride, saved the ride, hit the power button, but then this morning found it was down to 2% charge.  Plugged it in to the charger and it says its charging, but on unplugging an hour later it will not turn off and still says 2% charge.  If I hold down the power button it goes to the "send message to emergency contacts".  Won't charge and won't turn off

Seems to be the same as the (never solved) forums.garmin.com/.../garmin-edge-840-won-t-turn-off