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chamso256
User level: Level 1 (4 points)

iPhone 14 Pro Max battery drains quickly and has poor standby on iOS 27

i have iPhone 14 pro max , and in the iOS 27 the standby is terrible, and the battery does not hold like in iOS 26.6.1 And never like iOS 18.6.7

Posted on Sep 17, 2026 10:11 AM

4 replies

TahaHatipoglu
User level: Level 1 (18 points)

Sep 17, 2026 12:10 PM in response to chamso256

Quick battery drain after a major update is often expected. My iPhone 17 Pro Max had a similar issue but it turns back to normal after a couple charges. There are two main things happening:

  • After the first day of the update, your phone spends standby time by creating an index for Spotlight and Siri, which may result in mild to noticeable increases in heat and battery drain.
  • Even after creating the index, your phone may need to re-calibrate its battery indicator for the first couple of charge cycles, which might result in poor battery life but is not an indicator of poor battery health directly.

Same things happen when you first setup your new iPhone.


My 17 Pro Max turned back to normal after about 3-4 charge cycles. You should expect the same results unless there is a battery malfunction. iOS 27 itself is quite a stable update for it to drain battery life noticeably quicker. It could also be a product of the new CPU scheduler that came with iOS 27, which may take some time to calibrate for the first few days, but eventually using the CPU more efficient and with higher performance in the long term.


Other than these, you may try uninstalling un-used apps (some apps not optimized for iOS 27 may use resources more than regular after the update) or turn off app refreshes in the background for select apps. These will help increase your day-to-day battery life without needing the low power mode.

Mac Jim ID
User level: Level 10 (105,996 points)

Sep 17, 2026 12:19 PM in response to chamso256

You should expect that for about 4 days after the update and it is detailed here where you will see increased battery drain, extra heat, and even some UI lag until those background processes have completed. That is why we see those same reports after every update and also why Apple has produced this Support Article.

About Apple software updates - Apple Support


Jeff Donald
User level: Level 9 (64,078 points)

Sep 17, 2026 12:13 PM in response to chamso256

Hi, that’s normal for the first few days. Your iPhone is syncing, indexing, backing up and optimizing data. Make sure you plug your iPhone in at night, connected to WiFi and locked. This allows a lot of background activity to occur when you’re not using your iPhone.


What’s the battery health for your iPhone? My iPhone 14 Pro Max, just hit 80%. Once it drops below 80% Apple recommends replacing the battery.

Originally posted at discussions.apple.com/thread/256359122