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paul.s
User level: Level 1 (9 points)

iOS 27 is Draining My Battery Even When Plugged In

My iPhone 17 Pro running latest iOS 27 is draining battery even when plugged into a type-c charger (Anker 140W).

My charger have a wattage output screen and both times it is showing output of 0W. I basically have to unplug the usb-c cable and re-plug it in to solve the issue. This never seemed to be a problem on iOS 26(I always use the latest version).

My observation is that it would charge to full (I have optimized charging switched on but still set the charge limit to 100%), and then it will not keep it charged and instead start draining while being plugged in.

I am wondering if people are seeing similar issues.

Posted on Sep 24, 2026 5:41 PM

7 replies

Lawrence Finch
User level: Level 10 (244,490 points)

Sep 24, 2026 5:56 PM in response to paul.s

To troubleshoot, start by changing components, one at a time. Start by changing to a different power source. Then a different cable.


Also, go to Settings/Battery/Battery Health and see if it says “Normal” for battery health, and also verify that Maximum Capacity is above 80%. Also report the cycle count.


paul.s Author
User level: Level 1 (9 points)

Oct 8, 2026 3:38 PM in response to arast1

Yes. Rarely but it happens.


This time, without disconnecting anything, I force restarted the iPhone and it started charging again. So almost certainly a PD negotiation bug.


Out of curiosity, what type of charger and cable were you using?


thecmpguru
User level: Level 1 (8 points)

Oct 12, 2026 12:33 AM in response to paul.s

I experience this on my iPhone 17 as well. Only started after upgrading to iOS 27. Disabling Optimized Charging is the workaround.


It’s not an issue with the charger or cord. Same phone, charger, and cord worked fine before the update.

Bob Timmons
User level: Level 10 (199,348 points)

Sep 24, 2026 5:55 PM in response to paul.s

Optimized Battery Charging was designed to charge the phone by connecting it to the power supply late at night and leaving it connected all night......every night.


More details about Optimized Battery Charging are here:


When to charge your iPhone or iPad - Apple Community


It will take a few weeks for Optimized Battery Charging to learn your routine. The battery will charge relatively quickly to 80% and then it will rest until the next morning when it charges up to 100% before you get up in the morning. This is normal.


Are you saying that when you are sleeping the battery is draining?


paul.s Author
User level: Level 1 (9 points)

Sep 24, 2026 6:42 PM in response to Bob Timmons

Are you saying that when you are sleeping the battery is draining?

yep. I think my first screenshot is probably around 80%, and drained until 63% when I took the screenshot. It was on charger the whole time.


The second one did something similar. It looks like I can only recover after unplug and replug it. Still showing that it is connected to the charger for the entire duration.

paul.s Author
User level: Level 1 (9 points)

Sep 24, 2026 6:38 PM in response to Lawrence Finch

Battery Health: Normal

Capacity: 97%

Cycle 242


I'll try connecting to my mac tonight to see if this is still an issue.

arast1
User level: Level 1 (12 points)

Sep 28, 2026 2:09 AM in response to paul.s

have you managed to solve the problem? I am having the same problem rn

Originally posted at discussions.apple.com/thread/256364489