Apple Watch battery draining fast after watch OS 11.5 update

Ok - After hitting final frustration yesterday I have Repowered both devices (Watch 9 and phone), reset sync data and unpaired and repaired the watch. It looks like maybe thats done it. For people saying it takes 24 hours I have an iphone 15 pro with 62GB free, an Apple Watch 9 with 53 of 64GB free (Very few apps) so there is no way it should have taken DAYS to finish synching. I did track my sleep on the 25th so I'm picking I did the update that morning when back on charge (Sunday) and by Tuesday it was still running ridiculously down on battery life so it had all of Sunday, 24 hours of Monday and into the day Tuesday and wasn't "completed". Apple needs to improve the update experience as we shouldn't have to jump through random hoops hoping one of them will fix an unknown issue. Today after yesterdays restarts, repairing etc my watch is on 93% after getting it off the charger 2.5 hours ago which seems about right.

So basically if you are having this issue - Full power off and back on the watch, likewise phone, unpair and repair the watch from your phone. This is easy and restores your last backup which is run when you unpair I think (Certainly it was last run a short time ago). Hopefully that'll see your battery behaving again.

I had a thought on this (prompted by someones comment elsewhere). I'm back in this position after updating to Ios 26 and someone make a comment that some of the post update tasks will only run while the watch is on the charger - If this is true that might explain why some people have little issue and others it goes on for a long time.

I wear my watch to bed and pop it on charger for an hour during my shower and breakfast meaning its rarely on the charger for long periods.

This time after the ios 26 update I'm putting the watch on charge over night for a couple of nights to see if that completes the background tasks - In part because it'll barely make it through the night anyway.

If 3 nights on the charger hasn't fixed it I'll be unparing and repairing again.

It will take 24-48 hours for the new operating system to finish it house keeping, as well as resync things it wants from the iPhone. Power cycle the Apple Watch and your iPhone (at least once, but maybe once or twice a day until the Apple Watch battery consumption returns to normal. The MacObserver.com How To Fix WatchOS 10.3 Battery Drain Issue on Apple Watch https://www.macobserver.com/tips/how-to/fix-apple-watch-battery-drain-issue-after-watchos-10-3-update/ Also see: https://discussions.apple.com/docs/DOC-250007078 For some steps that are not in the MacObserver article. iPhone -> "Watch" app -> General -> Reset -> Reset Sync Data Again it may take a day or two for the rsync'ing of data to settle down. As a point of reference, my Apple Watch Series 4 with 90% battery health maximum capacity, was back to normal after 24 hours (watchOS 10.5). I did 1 mid-day recharge, and I power cycled my Apple Watch and iPhone twice.

After rebooting my watch (letting it completely discharge), the drain problem seems to be fixed, or at least be less noticeable. I am able to survive for about 36+ hours on a single charge now. My battery health shows it is at 87%.

I had this issue that I normally wear my Watch 9 to bed and charge it while in the shower in the morning and it wouldn't even last through the day.

As I said earlier I had to unlink the watch and relink it and after that its back to behaving normally.

It sounds like a pain but it takes a little time as the backup that it does before unlinking and the relink take a whole but its a painless process that loses no data at all, not even the days steps etc.

Unpair it and then start the pair process again telling it to restore from the backup it makes when you unpair and your poor battery life will be a thing of the past. I had to do it on my Apple Watch 3 every time I did an OS update as there wasn't enough memory on the device to complete the updates so I guess I'm more used to it than most but it truly is a problem free process.

I fixed mine, First I tried everything that was suggested... restart both watch and iphone, turn off settings like wake on wrist rise, etc.. I even had everything shut down, and it's just sitting on my desk. I finally tried the last resort and it worked so do this first to save time: Unpair the watch from the phone following the Apple instructions and re-pair and it works great, don't ask me why.

Ok, after almost a week of having to charge my Apple Watch 3-4 times a day after this update, it seems to be fixed when I did not wear it and left it on the charger for about a day. The battery life is back to lasting about 2 days. I also have not seen the overheating issue come back so looks like I am in the clear.

Check out this article If the battery in your Apple Watch drains too quickly - Apple Support

"Even though you can use your Apple Watch immediately after you update watchOS, certain tasks related to the update continue in the background and might affect battery life."

My husband and I both shutdown and restarted our watches today in hopes

that it would help with the battery drain issue. We both believe that it has made a difference, so maybe start with that if you are also having this problem.

I did experience this problem on apple watches, I now have an Ultra Gen1 bought 2+ years ago. For a couple of months now, I just run my watch on 'Low Power'. I can get 2.5 days easily on one charge. Try low power to reduce consumption. Doesn't fix the issue, but it helps so you aren't married to the charger.

Yes, I am also having this issue as well as my Apple watch overheating, it is already at 45% on low power mode after only 7 hours. This should be normal after updating though because the update still runs in the background for a few days, it should hopefully even out after a couple of days.

-Appleking16

Apple Watch 9 thats always worked like a dream. I wear it all day, track one or two workouts, wear it to bed and then charge it for an hour while in the shower and having breakfast. Since the update I charged it overnight, tracked one half hour walk and by 9pm it was complaining the battery was low and needed charging.

I see someone said it came right - I might shut down and full restart the watch. I'll report back if that changes its health but initial response is 11.5 has ruined my battery life.

I have a series9 watch and since the 11.5 update my battery is draining so quickly I am having to charge twice a day in order to be able to track my sleep and wear my watch at all times. My husband is also having battery drain problems with his 2nd gen SE. I have had an Apple Watch for almost 9 years and I do not recall ever having my battery drain so quickly with any other watchOS.

Ouch - Just restarted - Noticed after restarting my battery from taking it off the charger at 9am is already down to 89% by 10:20am. Not used it at all for anything - Just worn. We'll see if the restart helps at all. Otherwise I'll unpair and repair it next.

EDIT: I've gone ahead and unpaired and repaired as after 10 minutes it had gone down another 2% (Ok - Might have been 1.5 but not satisfactory). We'll see how that goes.