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.

MBILC wrote:

Sounds like another "Battery-Gate" like when Apple did those changes to older models claiming it was to "protect the battery" meanwhile they then reverted it due to the backlash, was more like a way to try and force people to buy a new phone :D

But in this case, it is also happening on iPhone 18s....

You battery graph only shows 4 days of use which means the background processes are still being performed to index the files in the background. The first day you have post is so negligible I would not even count it. None of your tweaks will do any good and truthfully even after indexing, crippling your phone in that way will have little effect on battery usage. It has been seen to take about 5 - 7 days to fully complete. Downloading and indexing the Siri AI models may even take longer.

You need to plug your phone in and have it connected to power all night, every night for those processes to complete faster. This happens after every update and setting up a new phone and also why you see those same reports over and over again until they eventually go away once they let their device finish the spotlight indexing. It is so prevalent that Apple even long ago added a Support Article explaining that you should experience battery drain, increased heat, and even some UI lag until that indexing has completed.

About Apple software updates - Apple Support

People report the same thing after every update, and you can even go back in this forum and see the same thing for every new device and every new iOS update. None of that is unusual and as always, you never hear another thing about it after a couple of weeks. It was the same for iOS 26, iOS 18, iOS 17, iOS 16, etc, have a look.

The only thing missing from your screenshots are the apps consuming your battery after you tap View All Battery Usage on that screenshot. Go ahead and post both Battery Graphs you see there along with at least the top 6 apps and also on the bottom there is a section for System Usage, so post if you see anything there.

What is the purpose on going off an a Battery Gate tangent. That was nothing to do with battery draining and was for throttling the CPU. If that was going on, you would actually have longer battery usage. It seems like you may be confused and nothing was reverted. The only change was that you they added a message in Settings that tells you in Peak Battery Performance that your CPU is being throttled and you can turn it off where you may experience shutdowns due to the battery degradation. The CPU was throttled then and still continues to this day for that same reason.

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.

dmctom wrote:

iPhone 15 Pro Max. Battery drain is so severe that I’m having to charge 2-3 times per day…. Same usage, same apps. iOS 27 has an issue. It’s been weeks

There are 2 things you need to post:

• The Battery Health percentage at Settings > Battery > Battery Health.
• The Screenshot at Settings > Battery > View All Usage that includes both battery graphs and the top 5 apps consuming your battery. I suggest choosing yesterday in your Daily Battery Graph so the app usage includes a full days worth of data to provide a complete picture. If you see a large amount of Other Usage on the bottom of the screen, then post that as well.

Dinitha_Wickramasinghe wrote:

I'm having the same issue with my iPhone 17 pro since i have updated to iOS 27. My biggest concern is my phone keep getting Heating even after fully shutdown 😕😕

First 2 days after updating went without an issue. No battery drain, No Heating

But after those 2 days my phone began to heat and drain battery like crazy 😕

I have waited for the iOS 27.0.1 hoping that it would fix the issue. But it didn't either... 😕

I have tried:

1. Factory data reset

2. Turning off siri beta

3. Fresh install iOS via restoring using my MacBook pro

Nothing fixed it yet...

*Only after Turning off wifi completely drops the heat by some amount

My biggest concern is how iPhone keeps getting Heating when it is powered off?? I shutdown my phone before 6 hours of sleeping. Then after waking up i grabbed my phone and noticed it is getting hot even when fully powered off (not powered on yet).

Then after powering my phone on i realized that more than 30% of battery drained during night even when phone was fully shutdown 😕😕

My phone is only just 6 months old. I have another 6 months of apple care warranty. But I'm fron sri lanka we don't have apple stores here. I imported this phone through a reseller by paying 2X the value of the phone

My phone has never dropped. No damages. And no water damages.

I don't know why this happens to my phone 😕

I hope apple will fix my phone with upcoming ios 27.2 🥺 otherwise i will have to ship my phone back to japan and claim apple care warranty. And the process will take about 2 months 😞

Hi, that’s quite a bit of a rant. I get it your frustrated by your experience with your iPhone 17 Pro.

Everyone posting and commenting are just fellow Apple users trying to ease the frustration and bring things down a notch.

Apple and Apple Support don’t participate here. They moderate posts, but that’s the extent. Your post and frustration don’t get escalated to Apple engineering.

You’ve really got one option to achieve a successful resolution to the issue. Open a support ticket and continue to escalate the issue to Apple engineering.

What exactly do you expect just a fellow Apple user to accomplish your behalf?

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.

Your battery is fine. The update is still indexing all of the data on your iPhone and will continue to do so for another few days.

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

Connectivity Assist also sends traffic over cellular that your Wi-Fi network blocked, so home ad blockers like Pi-hole get skipped. Write-up and proof here: iOS 27: Safari ads bypass Wi-Fi ad blocke… - Apple Community