IOS 27 battery drain issue

G_55_D wrote:

100% having the same issue. Updated to iOS 27 last night and within 2 hours of waking up my battery is on 81%. I hate this

Last night? You have about 4 more days to go where you will see increased battery drain while the files are being indexed in the background. There is also Siri & Search Optimization being performed and updated object detection algorithms on all of your photos.

You should be using Optimized Charging and charge your phone all night, every night. This will give you the best chance for those processes to be performed quicker. Not only will you see increased battery drain during this time, but also increased heat and you may see some UI lag. This is not specific to iOS 27 and occurred on previous updates as well, Apple has even provided a Support Article to explain this and what to expect immediately after the update. That is also why you always see these same posts after every update.

About Apple software updates - Apple Support

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.

Something that might help with battery on iOS 27: turn off Connectivity Assist. It's Wi-Fi Assist with a new name and a new spot in Settings.

When your Wi-Fi gets weak or stops loading, your phone jumps over to cellular to keep things working, then jumps back. On spotty Wi-Fi it can do that over and over. All that back and forth keeps the cellular radio busy, and that drains the battery.

You have to turn it off in two places. First, go to Settings > Wi-Fi, scroll down to Connectivity Assist, and turn it off. Then tap the little (i) next to the network you're on, scroll down to Connectivity Assist again, and turn that one off too.

That second step is the one people miss. I turned off the main switch and it was still on for my home network.

Ayush_27_0 wrote:

https://discussions.apple.com/content/attachment/e5d60031-0122-4c5e-b1c7-a34f2ae212d7

Not enough data is represented in the apps using the battery since you are showing today and that is only for a couple of hours. What you need to do is tap View All Battery Usage and post both battery graphs on that page and the top 5 apps consuming the battery. On the first daily graph, choose Yesterday so the data shown below that for app usage will include a full days worth of data. The graph indicates quite a bit of Background Activity being used and that will show which apps are the cause of the battery drain for that day. If you have a significant amount showing on the bottom of that page under "Other Battery Usage", then post that too.

Also we don't know what your Battery Health is, so let us know what yours is at Settings > Battery > Battery Health.

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.

Welcome and thank you for reaching out. 🤗

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 ➢ Battery.

If you need more help, contact Apple Support directly.

Take care!

Smiliñ 😎 Brian | Community Volunteer

Chumbanga wrote:

I have a 16 PM and battery issues with the iOS 27 update please look into this.

You are not speaking to Apple here and haven't provided any information for other community members to offer any assistance.

• When did you update?
• Have you let your phone charge all night, every night to let the background processes complete?
• What is your battery health at Settings > Battery > Battery Health?
• Post a screenshot of the 2 battery graphs and the top 5 apps consuming your battery at Settings > Battery > View All Usage.

Normal and expected after a major iOS update. The battery is working overtime and will be for the next few days until everything is indexed on the iPhone.

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?

Following up on this, yesterday I found this YouTube video explaining a reason for battery drain with iOS 27, and that seems to make sense with current state of both my iPhone and iPad, an improvement of battery performance from one day to the next.

Check it out:

https://youtu.be/on8DdkxGbFk?si=-3_56aTaoK8MJjun

I am getting really bad Battery Life on my "new" iPhone 17 Pro Max. Getting like 3-4 hours maximum 5 hours screen-on time. I updated first day as the IOS27 came out, and really hoped that it will be better. But 11 days after the updated it did not change, i have already done every possible software thing, did the force restart. Only did not do the Mac restore option. And things are not getting better. Im like really long Apple user, have every bit of their Tech, but I am becoming really disappointed, and thinking of going somewhere else. I do not know if the guys at Genius bar can do anything?

To try to stop the rapid battery drain I put my iPhone 15 Pro in low power mode. The battery reduced 12% in two hours. Low power mode helped a lot.

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]

Yup even my 17 pro max is draining really bad since updating to ios 27. I even got the message stating that “your iPhone has been used more than usual since upgrading ios, and this may affect battery life”.

i hope this gets rectified before the battery life actually goes bad.

The same for me.

I upgraded to iOS 27 last night; my 15 Pro still has a decently healthy battery which usually lasts all day, charged at 100% starting my day at 6 am, to ~10% at around 11 pm.

Today it’s 3:09 pm and already down at 24%