Before the last update my battery would easily last all day and night. I’d even have enough to keep it going until the afternoon. Since updating last night to watchOS 10.1.1, the battery on my Series 8 has been awful. I’ve not used GPS or cellular and had my phone with me all day. Anyone else had this issue? I know I only charged it to 88% this morning but I can’t remember the last time I had to top it up in the evening before a workout.
Your watch is possibly caught in a sync loop with something in your iCloud account. It’s continuously trying to sync something. This happened to me about a year ago and it ended up being reminders however it could be anything that syncs with iCloud. The issue was on the server side and only Apple tech support can fix. It took about a week working with a senior advisor but one they determined what was caught in the sync loop the fix was quick.
This could be your issue.
How could you figure it out? Did you end up disabling some services?