It's been broken since firmware 3.90 released February 2018 and the error has been posted in these forums loads of times. As you've discovered the workaround is to do a full power off/on recycle.
There is a simple workaround to this known issue. To me it happens when I let the Edge charge. By itself it goes to sleep mode when changing is completed. If you use it after that it will have the battery stuck at 100%. However wake it up, do a complete shutdown (red Power Off button on thouch screen). Once this proper shutdown is done, the battery % will work just fine after reboot. I got into the habit of, after charging, unplugging the device, waking it up, doing a shutdown. After that all is good.
Yes, we are living with this bug for over a year!! Can't believe.
Instead of releasing funny features like accident alert or sharp bend warning, how about getting your homework done, Garmin, fixing basic functionality like battery level display?
I purchased an Edge 1030 this spring, and I think it came with firmware 7.50. The battery percentage worked fine until I upgraded to 8.00, then it got stuck at 100%. I'm not sure if it started working correctly (i.e. decreasing from 100% without a full power cycle) after it all of a sudden powered off during a ride. After upgrading to 9.00 it was stuck back at 100% until I power cycled it tonight. My point is the battery percentage did work for me after firmware 3.90 but before 8.00. Is the solution that one must fully power cycle between rides or just after a firmware update?
I still wonder why not just turn it off after a activity? Battery percent works fine it it is powered on. Why use sleep mode when the start up time is within seconds of a power on start?
