Garmin 55 switched off while running.

Hi
Can't offer a solution, but I have started experiencing this issue as well. Seems to be if the battery is less than 45% for me.
Also, I've noticed that I charge it to 100%, then within an hour or so it is down to 100%.
Seems to have started since the 11.03 firmware update.

I'm not able to offer a solution but can confirm it is happening to me as well. Seems to occur if battery is below 45%.
If I start the watch again it is stuck on 2km though I'm hearing the beeps for each km after that.
Battery charged to 100% drops down to 90% within an hour.
Seems to me that it started after the update to either 11.02 or 11.03.

4125951 said:

Seems to me that it started after the update to either 11.02 or 11.03.

As they used to say in ancient Rome: after this, does not mean because of this.

I had a similar problem after I discharged the battery very deeply. The watch had already gone out because of the discharge, but I turned it on again and waited for it to go out again. I calibrated it stupidly. After that, the battery degraded sharply, first the watch started turning off during activity, then just after an hour or two. Moreover, when charging, the charge immediately showed high. In the end, they started working only when the charger was connected, and then they stopped turning on at all. I had to change the battery, this was a year ago. With the 11.03 firmware, there are no problems, the charge holds the same as before.