Iphone 16 battery drain and heating issues after ios 26.5 update

you're not imagining it. Lots of iPhone 16 users have the same drain and overheating after iOS 26 so it's a known software issue not your battery. Your hardware is fine 98% health is perfectly healthy which is why Apple keeps saying nothing's wrong. But a month is way too long so don't just wait it out.

Try these:

1. Hard reset. Volume up, release, volume down, release, then hold power until the Apple logo shows. Clears stuck processes and often fixes it instantly.
2. Turn off the new visual effects. Settings, Accessibility, Motion, then turn on Reduce Motion and Prefer Cross-Fade Transitions. The liquid glass effects are battery heavy.
3. Settings, Battery, check the last 24 hours. If one app (especially Instagram or Facebook) is eating 40%+, delete and reinstall it.
4. Update all your apps manually in the App Store and make sure you're on the latest iOS.

If nothing works, back up and do a full restore through a Mac or PC (not iCloud). It's annoying but clears whatever got stuck. The overnight drain you're seeing is severe so I'd try that before giving up.

Higher than normal battery utilisation is expected after performing a system software update. Post-update, the device will be running significant background housekeeping tasks - such as reindexing and download of additional software assets (e.g. LLM models). The additional CPU processing, inevitably, leads to increasing temperature.

Normal battery utilisation can be expected to return within a few days. Keeping your iPad connected to its Power Adapter over this period can speed-up the process - as the iPad will maintain peak operating capabilities and its WiFi connection while connected to external power.

If your iPhone is not operating as expected, try a forced-restart - as this will often clear an isolated or post-update software issue:

Force restart iPhone - Apple Support

If the problem persists after performing the restart, it may be necessary to reset your iPhone settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:

How to back up your iPhone, iPad, and iPod touch - Apple Support

When you are happy to proceed, you can perform the reset from iPad settings:

Settings > General > Transfer or Reset iPad > Reset > Reset All Settings

If the problem still doesn’t clear, the next step is to reset the iPhone to factory settings:

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Otherwise, you would be well advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPhone, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assist with troubleshooting:

Genius Bar Reservation and Apple Support Options - Apple

shubhangi80 wrote:

....since one month when I updated my iphone to ios 26.5.

Not every issue an individual encounters on their device can be attributed to an iOS update. If the update itself were the root cause, then every device running that same version of iOS would exhibit the identical problem. In such a scenario, the forums would be flooded with countless posts reporting the same malfunction, creating an unmistakable wave of complaints that no one could possibly overlook. The absence of such widespread reports strongly indicates that the issue is not systemic, but rather specific to the device in question.

"If battery life is less than expected after an update

If you notice that your battery life has decreased after updating your device, wait a few days and then check again."

This Apple Article clearly states the above : If the battery in your iPhone or iPad drains too quickly - Apple Support (IN)