Why is my iPhone battery draining fast after iOS 18.4 update?

It was the mail app for me running in the background consistently even with background app refresh off. It was showing an hour by hour usage in the background ( thats a full hour of working in the background and minutes on the screen ) when it should be minutes in the background. The only fix I’ve found after a fresh install of iOS ( this didn’t work ) was to delete the mail app and use a different mail app and this is now working correctly with minutes in the background. This isn’t because of it’s “an update so the iPhone will be configuring in the background and power and thermal performance might be affected” this was something else. Oh and my iPad doesn’t have any issue at all.

mathivanan275 wrote:

This has been happening to me since 5 days after the 18.4 update

What apps are consuming the battery at Settings > Battery and scroll down to view the apps over the last 24 hours. You can post the screenshot for those apps as some have already been identified as having an issue with battery consumption even when they are not being used. The apps are updated in the background much more frequently then the iOS updates and many times go unnoticed since intervention is not required on your part to update them. Many times those updates will also include bugs as been noted by Meta with a previous battery consumption problem.

For example, Facebook has been updated 1 day ago, 6 days ago, and 1 week ago, all which could coincide with an iOS update. Users are more likely to associate an issue with an iOS update while ignoring the app updates that can also cause problems, especially when related to battery consumption when those apps are using Background Processes.

Also, iOS 18.4.1 is already out. Please update.

After the update, try to power down the phone, and start it up again. It should operate normally after a day or so (once the system is done indexing and completing all the background tasks needed to get the system all ready to go)

ArshBaghadiya wrote:

Same here after the update. 2 charge cycles daily

There are certainly cases where that is possible, but without any other information it is hard to determine if it is a problem:

• Are you starting your day at 100% or using Charge Limits?
• Have you identified the apps using the battery? You can post a screenshot if you wish that shows the graph along with the top 5 apps battery consumption over the last 24 hours.
• Which update are you referring to as 18.5 is the latest update and the post is about 18.4?
• Have you given it 3 days after the update to index files for spotlight search and analyze photos for new object detection definitions?
• What is your Battery Health percentage?
• Have you performed a Force Restart on your device?

After an update, your iPhone must work extra hard to run additional background tasks. Some of these include indexing which is sorting all your data on the new software and moving features to the right places. Which you can experience an increased battery drain. When the tasks are fully complete, which usually takes a few days to a week, your iPhone will return to normal conditions.

You should also read my User Tip which further explains this in detail:

Addressing the Common Increased Battery D… - Apple Community

“Why is my iPhone battery draining fast after iOS 18.4 update?: Since i update ios 18.4 version my device battery very fast drain to much , please anyone who know how to fixed this bugs”

———-

Troubleshooting iPhone Battery Draining After an Update:

A. Battery Drain Info:

The iPhone battery will drain, unless it is plugged in and charging. With lots installed, the charge would be slower. As for how fast it would drain the battery, that would depend on the battery health and the volume (sound) you use. Apple recommends you get a new battery when the Battery Health reaches below 89%. So, see if it’s time for a new battery.

1. Go Here: iPhone Battery and Performance - Apple Support
2. Scroll Down: to "Your battery's maximum capacity"

B. Verify the Baterry Health Percentage:

Apple recommends you get a new battery, once the Battery Health reaches 80% or lower. When the Battery Health is 80% or lower, it is time for a new battery. Unfortunately, these if no way to know how, nor when, then percentage decrease occurred. So see if it tine for a new battery...

1. Go To: Settings
2. Tap: Battery
3. Tap: Battery Health
4. View: [the percentage]
5. Is it 80% or less?  If so, it is time for a new battery.

C. Troubleshooting the Battery:

• iPhone Battery and Performance - Apple Support

• Charge and Monitor the iPhone Battery - Apple Support

• About the Battery Usage on your iPhone - Apple Support

• About Optimized Battery Charging on your iPhone - Apple Support

• If you see "Your iPhone Battery may Need to be Serviced" - Apple Support

• Use Low Power Mode to Save Battery Life on your iPhone - Apple Support

D. Report this to Apple:

Do your Part: This seems to be a commonly reported bug in these forums. Question is: "How many people have let Apple know about this bug?"  Apple wont get back to you directly, but the more feedback they receive on this, the more they will know what bugs are occurring, and what needs to be fixed. Apple will know nothing of your issue, if you don’t report it to them.

Giving Feedback:

1. Go Here: Feedback - iPhone - Apple
2. Select: "Bug Report" for the "Feedback Type"
3. Comment on: That this all started after installing an update. Include the URL of this thread.
4. Proceed From there as necessary

AlmightyGTR wrote:

mail sync set to auto.

How is it possible for mail app to all of a sudden start using so much battery life in background?

Try again. ⇣

1. Open Settings
2. Tap Apps
3. Tap Mail
4. Tap Mail Accounts
5. Tap Fetch New Data

Make adjustments as needed.

Your mail will fetch when you open the Mail app, not in the background when you’re not using it.

Good luck! 👋🏼😉

AlmightyGTR wrote:

Force Restart your phone:

• Press and release quickly the Volume up button
• Press and release quickly the Volume down button
• Press and hold the side button until the Apple Logo appears. It could take up to 15 seconds before the Apple Logo appears and you will want to ignore anything else you see on the screen during that time while holding the side button.

Do this after you make sure to have updated to 18.4.1

Cantthinkofanythingelse wrote:

It’s happening to me too. After charging to 100% and listening to music for an hour, nothing else, just music playing, my phone is drained to 60% and continues to rapidly drop. Very frustrating.

Unfortunately without providing any additional information, you only option is to contact Apple directly or schedule and appointment at the Apple Store.

• Contact Apple Support - Apple Support
• Genius Bar Reservation and Apple Support Options - Apple

The type of information that would be relevant is:

• The Battery Health when viewed at Settings > Battery > Battery Health & Charging > Maximum Capacity.
• A screenshot of the battery consumption at Settings > Battery and scroll down to reveal the graph along with the top 4 app on the list that shows consumption over the last 24 hours. It is best to provide this screenshot after the battery has decreased to see the cause.

sadanand83 wrote:

2-3 times i need to charge it and while charging as well it's getting too much hot and giving high temperature warning on screen.

First, Force Restart your phone:

• Press and release quickly the volume up button
• Press and release quickly the volume down button
• Press and hold the side button until the Apple logo appears. This could take up to 20 seconds and you will ignore anything else on the screen during that time until you see the Apple logo.

If you continue to see the high temperature alert without the obvious condition of being left in full sunlight, then contact Apple directly or take to the Apple Store for diagnostics.

Contact Apple Support - Apple Support

maklmape wrote:

My battery health went down from 100% to 95% within 17 months, but just during the last month it went down from 95% to 91%. Its alarming and I dont know what to do to stop the battery to go bad this fast. Im still using the same charger, using charging cap to 80%, using the phone still the same. Its suspicious it happened the same month the 18.4 update was released.

• Which iPhone do you have?
• How many charge cycles are showing?

For an iPhone 15 and newer, you should see a drop of about 1% battery health for every 50 charge cycles. The battery health is not calibrated until the Charge level has reached 100%. This will happen automatically on occasion even when you have set a charge limit, but if you do not allow it to happen, then you will see larger drops in Battery Health since it was not able to calibrate previously.

Fixed it by deleting 4000+ E-Mails in my iCloud mailbox! Since then the Mail app is no longer draining my battery. I hope Apple is reading this. But thanks for the new iPhone 16 Pro that I got because the Genius Bar employee thought it was a hardware issue.

AcridKobashi wrote:

iPhone 15 Pro Max, no issues with battery until recent 18.4.1 update. Ever since (it’s been a few days already) I have to charge at least twice a day.

hope this gets fixed!

Unfortunately without providing any additional information, you only option is to contact Apple directly or schedule and appointment at the Apple Store. There have been the same reports that the update has now given them all day batter life.

• Contact Apple Support - Apple Support
• Genius Bar Reservation and Apple Support Options - Apple

The type of information that would be relevant is:

• The Battery Health when viewed at Settings > Battery > Battery Health & Charging > Maximum Capacity.
• A screenshot of the battery consumption at Settings > Battery and scroll down to reveal the graph along with the top 4 app on the list that shows consumption over the last 24 hours. It is best to provide this screenshot after the battery has decreased to see the cause.

AlmightyGTR wrote:

Ran phone in battery saver, to just get by till this bug is fixed. Guess what, slope of battery drain during idle does not change even in battery saver mode. 

It may be better for you to schedule an appointment with Apple or contact them for remote diagnostics. Since the same thing has not been reported for all users after the update, I would not be waiting for a bug fix.

• Contact Apple Support - Apple Support
• Genius Bar Reservation and Apple Support Options - Apple

brendabee22 wrote:

Mine too!! And it wont charge even with an apple charger and block. It literally will lose battery power while plugged in!!! I’ve tried 8 different chargers and blocks and I’m having the same issues.

Contact Apple directly or schedule an appointment where they can perform diagnostics on your phone. The one thing to check is for lint or any obstructions in the charging port of your iPhone, other than that it would appear to be a hardware problem. A phone that is unable to charge or the battery level is dropping while plugged in is a much different matter.

• Contact Apple Support - Apple Support
• Genius Bar Reservation and Apple Support Options - Apple