Bumping this thread to get some help.
I’ve got a brand new Series 6 (44mm GPS) running watchOS 7.3 and paired with an XS that seems to be experiencing all of the issues described in this thread.
This is actually the second one I’ve been sent — Apple swapped out the first one after I complained that I was consistently only getting about 6-12 hours of battery life out of it, even when doing absolutely nothing with it (no workouts, no dedicated audio streaming... nothing). I'm using a Chronograph Pro face with four complications (date, weather, rain, and reminders) and default settings: always on / handwashing / wake to raise switched on, etc.
But now it’s also happening with the second one they sent and I’m starting to get super frustrated.
I've tried unpairing / repairing / wiping multiple times, and each time I do I get a solid 20-24 hours of battery life out of the thing -- but only on the first battery cycle. After that the battery goes to complete garbage, often maxing out somewhere between 6-8 hours of battery life. Mind you, this is on DAY TWO of having the device, with virtually no activity.
I understand that I may need to give it a few days to settle, but I'm coming up on the two week return window and I don't want to cut it too close. My Series 2 - which I finally dumped two weeks ago because I couldn’t deal with the lagging OS and crappy battery life - lasted longer than my brand new watch on its worst day. And my wife’s Series 6 (40mm GPS) lasts at least three times as long as mine does in identical scenarios.
How accurate is it that I may experience inconsistent battery life (today it looks like I'm going to get about 12 hours out of it) for a few days after re-pairing, and how long should I wait before giving up on the thing?