Normally my Prime can be at 100% full battery in the morning when I get up if it was fully charged the night before. I leave cellular off, wifi off, bluetooth off, GPS off and have everything in the More > Background Cleaner > Battery Saver enabled to save battery power.
Yesterday I turned off an app I use for GPS and turned on GPS for an hour or so. When done I turned off GPS but forgot to turn off the App in Battery Saver. The watch had gone form 100% down to 65% in about 8 hours. Before going to sleep I turned that app back on in battery saver and did a ‘Clean’ function which I assume cleans memory of any apps not being used. I charged the watch to 70% before going to sleep.
When I got up the watch had turned itself off and would not turn on. I plugged in the charger which showed a red bottom battery which seems to be the way of saying battery is at 0% charge. After a few minutes it turned green bottom so I turned on the watch which was now at around 10% if I recall. Everything else was off as usual - GPS, cellular, Wifi, Bluetooth all off. I would like to understand why it ran down so quickly in 8 hours with everything off and memory having been cleaned and battery saver fully enabled for all apps listed. Maybe a fluke but it’s concerning it would lose that much charge in 8 hours with everything possible turned off and battery saving full on.