iPhone 16 Pro battery health plummeting after iOS 27 update (95% to 91% in days) + heavy idle drain

iPhone Q&A
1

Has anyone else noticed weird battery behavior on their iPhone 16 Pro since updating to iOS 27?

Before the update, my battery capacity was sitting at 95%. Ever since installing iOS 27, it has been dropping 1% every 4 to 10 charge cycles. It just dropped again to 91% within 4 cycles (currently at 329 total cycles).

What’s even stranger is the daily drain:

Max Screen Active time this week: 3h 28m

Daily routine: I still have to plug it in at 20% every single day despite barely using it for 3.5 hours.

Is iOS 27 stuck running some background indexing loop, or is the battery recalibration just acting up? Curious if anyone else is seeing similar numbers or found a fix.

2

Yes bro. many have reported it with even iPhone 17 models. its possible iOS 27 being the main reason here. today or tomorrow we are expecting iOS 27.2 update. expecting good improvements overall with batery performance due to bug fixes.

Do update once released then observe for 3 to 4 days and see if you notice difference or not. iOS 27 being major update does have bugs causing such issues. 27.2 and 27.3 like updates only brings more stable experience overall.

continue following the charging practice for now. we will see good improvements only after fixes.