I think I have a solution for this:
I have a Series 8. Battery health reports 80% capacity (after about 2 years).
Following my upgrade to watchOS 11.01, I was running out of power around 12-13 hours into the day. This was even worse if I had a workout (I sometimes train for 3 hours in a single day.) On any regular day, my battery was down to 50% by lunch.
I did the following this week,
which has improved things a lot:
- Update to watchOS 11.1
- (And I think this was critical) - I un-paired and re-paired my watch (loading the last backup) with my phone right after the update.
I have done this in the past and it seems to clear up a lot of issues, particularly with power management.
Yesterday, with no workouts, I finished the day with about 25% left (at 14-15 hours). So far today, I am at 50% after 8 hours and one workout. I have another workout for two hours this evening, but I should make it to 16 hours without going to low power mode, if I’m not mistaken.
So - unpair and re-pair, loading from the backup!