This was one of those things I had no control over; I woke up at 4am to get ready for a 200 mile ride, and saw i'd got 10.0 overnight. Hooray. I used UltraTrac for the ride, which was about 15h30 total duration, and 12h30 active recording/riding time. On arriving at the finish point, I paused, got a message "battery critically low, saving activity" and the device shut down. I thought UltraTrac was supposed to have 3 days of record time, and GPS was supposed to do 24 hours? What gives? Anything to be done about this?
After getting a software update, reboot the watch before using it. This is a general ritual we did in previous watches but I keep doing the same. Otherwise battery consumption was higher. But this may not be the case with your issue. Use of extra sensors and mapping functions may affect the battery life, especially if you keep the map screen always on, as the map is drawn every second. Also be sure it was in UltraTrack mode. Yesterday I did a 180 KM ride which recorded about 7 hours and my battery gone from %95 to %35 with heart rate, cadence, Tempe sensors and about two hours navigation. Of course out of recording GPS was alive for some time during stops. I advice having a power bank instead of UltraTrack mode.
I get around 5 percent per hour on MTB rides - that is without maps displaying. The maps kill the battery, so if you had those showing that would explain it. The custom watch faces were causing huge drains in some version between 9-10. Though haven't seen it reported in 10. Usually the opposite. Battery age perhaps - though mine is (a replacement) over a year old and still fairly consistent with battery usage since I got it.
You can switch off auto-updates under the settings-system menu too.
Good point by Sis too - forgot that. Have had it occur myself where taking it off charge, etc, would see a big spike in battery drain. Like a stuck process was sucking up battery. I always reboot after updates and charging. Even if the watch appears to have done it itself!
I was definitely in UltraTrac. I had connected to the watch, Speed sensor, DA 9100 power cranks (includes cadence), HRM chest strap, Di2. I did not use the watch to navigate, nor was it on the map page.
