iPhone 14 Pro/Apple Watch battery drain after iOS 26.3

MariusZuzus wrote:

Update: I tested turning off Bluetooth for 3 hours. The drain on both devices slowed down significantly.

Watch before (BT ON):•  7.5% per hour drain (idle).

Watch after (BT OFF):•  2.5% per hour drain.

This confirms a Bluetooth Communication Loop / Handshake bug•  in build 23D127. It’s not a hardware issue, but a faulty data sync protocol between the iPhone and the Watch in this version of iOS 26.

If that got top-ranking reply status then I give up.

I'm not sure who you think you're reporting this too, but if you thought to Apple Support, you're not. This is a user to user only forum, which Apple doesn't participate.

While you mention the iPhone model you own, you don't mention the Apple Watch model? What you've described could be aging batteries. iPhone 14 Pro was released in 2022, nearly 4 years ago. iPhone batteries don't last forever and if you check Settings > Battery > Battery Health - If the percentage is 80% or lower, the useful life of the battery has been spent and it would be time to pay Apple to replace the battery in your phone.

The same would be true for Apple Watch as they too don't have a forever battery.

You are welcome to schedule an appointment at your Apple Store Genius Bar to have both devices tested. You can do that with this link --> https://www.apple.com/retail/geniusbar/

Iphone and watch were both designed to last one day, not two.

Charge them both fully without charge limit, all night every night on your night stand.

https://discussions.apple.com/docs/DOC-250004641

https://discussions.apple.com/docs/DOC-250007078

My wife and I experience the same thing. She on 13 Pro and me on 16.

She also had a series 7 watch that suddenly would drain even faster, thinking it was just age we bought her a new series 11. She’s had it about a week now and it still loses about 60% of the battery over night when sleeping with it. That’s 60% with no screen on and no notifications, just the normal sleep tracking.

Webbson wrote:

My wife and I experience the same thing. She on 13 Pro and me on 16.

She also had a series 7 watch that suddenly would drain even faster, thinking it was just age we bought her a new series 11. She’s had it about a week now and it still loses about 60% of the battery over night when sleeping with it. That’s 60% with no screen on and no notifications, just the normal sleep tracking.

Sleep tracking needs a rigid recharge discipline. Just before bed, then between rising and the rest of the day.

No time (the main reason for a watch) is available whilst charging. You need to ask yourself if sleep tracking is necessary. What if the sleep pattern is abnormal, what can she do? What is abnormal? So what if it is? Most world leaders get by on 5 hours sleep a night.

Just saying that there is a lot to be said for charging overnight, every night all night, with the watch in Night Stand/bedside mode, normal alarm function, and sleeping better for not worrying about pointless measurements and dodgy alarms..

Other opinions are available.

What apps are showing large background activity? Do you have widgets associated with any of the apps?

Had you previously tried reset network settings before the reset to factory reset?

Where did you get 23D127 as latest phone build? I have 23D8133 26.3.1

MariusZuzus wrote:

Then you live in a region where updates are released earlier. 26.3.1 just arrived today about two hours after the issue was resolved. At least I know what to do next time.

They should be mirrored round the globe at the same time.