I've had my edge 520plus for about a 1 1/2 years with no trouble. I went to start a ride today and it powered up like normal but said the battery was at 0%. I remember it being about 40% when I stopped using it the day before. It stayed on for a couple minutes then died. I tried charging it later and it would not display anything on the screen but the screen backlight would come on for about 5 seconds if you pressed any button. It will still sync with my phone through garmin connect and also connect to my laptop. I did a software update and a map update also. I even somehow recorded a 10 minute activity that showed up after syncing it. I've tried resetting it with the different button combinations I've seen on forums but it just won't do anything other than light the screen up. It really seems to be functioning without displaying anything.