IOS 27 battery drain issue

After ios 27 update iphone 18 pm is draining battery fast. Might be even for iphone 17 series. Please fix this.

iPhone 18 Pro Max, iOS 27

Posted on Sep 19, 2026 1:00 AM

Reply
Question marked as Top-ranking reply

Posted on Sep 21, 2026 10:24 AM

ge_almazan76 wrote:
same here. after updating to ios 27 last week, the battery drain is insane. hope this gets fixed by the next update. thank you
  • Post the Battery Health percentage on your device at Settings > Battery > Battery Health?
  • Post the screenshot of the 2 battery graphs and the top 5 apps consuming your battery at Settings > Battery > View All Usage.


After every update, you always see the same posts about the update causing battery drain and that is due to the background processes that are performed after the update. That was true for iOS 26, iOS 18, and even those before that where those posts are still visible in this forum. For most that takes about 4 days, but with iOS 27 there are additional Search & Siri Optimizations that are performed so you may see a couple days more. Not sure what day you updated last week, but if it has been at least 6 days, then post the requested information.

15 replies
Question marked as Top-ranking reply

Sep 21, 2026 10:24 AM in response to ge_almazan76

ge_almazan76 wrote:
same here. after updating to ios 27 last week, the battery drain is insane. hope this gets fixed by the next update. thank you
  • Post the Battery Health percentage on your device at Settings > Battery > Battery Health?
  • Post the screenshot of the 2 battery graphs and the top 5 apps consuming your battery at Settings > Battery > View All Usage.


After every update, you always see the same posts about the update causing battery drain and that is due to the background processes that are performed after the update. That was true for iOS 26, iOS 18, and even those before that where those posts are still visible in this forum. For most that takes about 4 days, but with iOS 27 there are additional Search & Siri Optimizations that are performed so you may see a couple days more. Not sure what day you updated last week, but if it has been at least 6 days, then post the requested information.

Sep 19, 2026 1:34 AM in response to shireen67

Welcome and thank you for reaching out. šŸ¤—


A rapid battery drain after updating to iOS 27 can happen while the system reindexes and optimizes in the background, usually taking a day or two.


According to Apple: If you notice that your battery life has decreased after updating your device, wait a few days and then check again. Even though you can use your device immediately after an update, certain tasks related to the update continue in the background and might affect battery life and thermal performance. While they're ongoing, you might see the Insight Ongoing iOS Update in Settings āž¢ Battery.


If you need more help, contact Apple Support directly.


Take care!

SmiliƱ šŸ˜Ž Brian | Community Volunteer

Sep 23, 2026 9:19 AM in response to DirtDirtDirtDirt

DirtDirtDirtDirt wrote:
I have been around for plenty of iOS updates, and I understand a new update is not going to be perfect right off the bat. However, after only 1 1/2 hours of use I'm down almost 40% this morning. I realize this will probably get patched in a future update but the sooner the better, I don't make it through the day any longer without having to charge my phone. My capacity is at 88%, which isn't bad. So, I want to submit my info to try and get a fix for this going asap. My phone finished indexing last week and it hasn't improved the battery life in several days since. It's about the same.
Official Apple Support Community
Official Apple Support Community

According to your Daily Graph, you are still experiencing quite a bit of background activity. For a better picture of App Usage, I would choose yesterday in your daily graph so the data shown is for a full day and not just a few hours in the current day and post what you see there.


If there is an indexing process stuck after updating the OS, I would recommend to perform a Force Restart. Some users will do this after any update to do some additional house keeping.

  • Press and quickly release Volume up
  • Press and quickly release Volume down
  • Press and HOLD the Side button until the Apple logo appears. This step could take up to 15 seconds while holding the Side button before you see the Apple logo and you have to ignore anything else on the screen including the prompt to Slide to Power Off.


I assume it has been at least 5 days since the update and you are plugging your phone in all night, every night to allow the indexing to complete quicker. I am aware of the notification in Settings for Siri and Search optimization and understand that has completed, but there may be additional indexing performed after an update.


Sep 22, 2026 7:11 AM in response to shireen67

I've noticed two major issues with iOS 27 and my iPhone 15 Pro Max:


  1. The battery drains insanely fast. With iOS 26 I never had to pay attention to battery life. Immediately after installing iOS 27 I have to charge my phone throughout the day, even taking a battery bank to the gym. At one point I watched the battery drop from 17% to 13% within a couple minutes. And later from 11% to 8%.
  2. Multiple GAN chargers and high-wattage USB-C charge cables that worked well with iOS 26 are unreliable with iOS 27. Sometimes they seem to work normally, other times the charging lightning bolt is visible but the battery does not appear to be charging. The same charger and cables work reliably with my iPad Pro (that I will not upgrade) and MacBook Pro.


Battery Health is normal and Search & Siri Optimizations finished days ago but these issues remain.


Anyone else dealing with these issues and found a solution?

Sep 22, 2026 3:11 PM in response to shireen67

Hi,

I’m experiencing a serious battery drain and overheating issue after updating my MacBook Pro to macOS 27.

My MacBook Pro is practically new — I purchased it about two months ago — and before the update, the battery performance was excellent.

Since installing macOS 27, the behavior has changed dramatically. For example, if I leave the MacBook unplugged overnight, even without actively using it, I wake up in the morning and the battery is completely drained. The MacBook also becomes noticeably warm or hot while it is not being used.

This never happened before the update. Previously, the MacBook could remain unplugged overnight with very little battery loss.

I’m very concerned because the device is almost new, and this issue started only after installing macOS 27. Please investigate whether this is a known issue with the latest update and advise on how it can be resolved.


[Edited by Moderator]

Sep 23, 2026 9:00 AM in response to shireen67

I have been around for plenty of iOS updates, and I understand a new update is not going to be perfect right off the bat. However, after only 1 1/2 hours of use I'm down almost 40% this morning. I realize this will probably get patched in a future update but the sooner the better, I don't make it through the day any longer without having to charge my phone. My capacity is at 88%, which isn't bad. So, I want to submit my info to try and get a fix for this going asap. My phone finished indexing last week and it hasn't improved the battery life in several days since. It's about the same.

Sep 23, 2026 10:54 AM in response to maverick_spartan

maverick_spartan wrote:
Insane battery drain for my iOS 13 pro.
This is most of all the updates till date.

It’s amazing. I have seen posts almost identical to yours after every update in the past 19 years.


As you haven’t defined ā€œinsane battery drainā€ there’s nothing anyone can say about it. To me ā€œinsane battery drainā€ would mean that the battery is dead one hour after it is fully charged. Is that happening to you?


If you charge the phone overnight with Optimized Charging enabled (a Best Practice) it should not require charging during the day, until the next overnight charging. If it meets this standard then the iPhone is working as designed.

IOS 27 battery drain issue

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.