Battery backup degradation.

arindam_majumder wrote:

It has 82% battery health .

As I suspected. Your battery is on its way towards failing and within the next month or so, you'll need to pay to have the battery replaced. Your issues weren't caused by an update. Your issues are happening because the battery is having to be pushed harder since its capacity is diminished. Do NOT let anyone other than Apple and an Actual Apple Authorized Service Provider replace the battery (like BestBuy in the US). No one else has authentic Apple Batteries and if you let anyone else replace the battery, certain services won't work and Apple won't touch your phone in the future if you need service. Plus they won't take a phone in trade which has been tampered with.

Ps: Given the issues you're seeing, I'd ask Apple if you could get the battery replaced immediately. They usually recommend waiting until it dips to 80%, but it would help you to get the battery replaced now.

What is your current Battery Health? Open Settings > Battery > Battery Health - if it is 80% or less, which wouldn't be unusual for an iPhone released 3 years ago, the battery is failing at this point and it would be time to schedule a battery replacement at your closest Apple Store Genius Bar --> Apple Service and Repair for iPhone Battery - Apple Support

arindam_majumder wrote:

After ios 27.2 update my iPhone 15 pro max's

Not every issue an individual encounters on their device can be attributed to an iOS update. iOS 27 or later may have coincided with what you are experiencing, but that does not mean the issue was triggered by iOS. Coincidence in timing is not, by itself, evidence of causation.

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 a general, system-wide problem with iOS 27 or later, but rather something specific to the individual device, its configuration, installed apps, settings, hardware, or another interacting factor.

In short: iOS 27 or later may be a coincidence in timing, but there is no basis to conclude that iOS itself triggered the problem simply because the issue appeared after the update.

See what each update does: About iOS 27 Updates, About iOS 26 Updates, About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...

It surely is not iOS 27 or higher because...

I conducted a thorough search of this forum using the term 'battery drain after iOS update' and uncovered numerous posts detailing similar issues across various iOS updates. This suggests that iOS updates may not consistently be the root cause. Below are a handful of examples extracted from the search results:

• Battery draining issue after update IOS 26.6.1
• iPhone 16 Pro Max Battery AFTER iOS 26 Update
• Re: iPhone 12 battery life shorter after iOS 25.6 update
• iPhone 14 Pro Max battery drain after iOS 17.0.1 update
• iPhone 6s battery drain after iOS update 15.7.1
• Re: Battery draining quickly on my iPhone 13 after iOS 18.5 update
• Battery Drain rate after iOS 16 update
• My iPhone 13 battery is draining fast after iOS 18.3.2 update
• Battery Draining after the ios 16.5 update
• Battery Draining after updating iOS 18.1.1
• Re: Battery drain after ios 15.6 update
• battery drain after ios 10 update
• Re: iPhone battery drain after updating to iOS 16.3

Reports of battery drain issues appear across all models and iOS versions in this forum, suggesting the issue is device-specific rather than tied to any particular iOS version or model.

The measure of battery health deterioration/drainage is subjective and can vary depending on individual usage patterns. There is no universal standard to determine whether the battery health deterioration/drainage is normal or abnormal because it heavily relies on how the battery is used and maintained.

Protect & Prolong the Life of your iPhone's Battery:

1. About the battery usage on your iPhone, iPad, and iPod touch ...
2. Batteries - Maximising Performance - Apple (IN)
3. iPhone Battery and Performance
4. About Charge Limit and Optimised Battery Charging on iPhone - Apple Support (IN)

• Find out what to do if Optimised Battery Charging doesn’t activate.
• Find out what to do if your device stops charging unexpectedly.
• Find out what to do if you think your battery is draining too quickly.
• Find out how to charge and maintain your iPhone battery.

Watch a Video made by Apple:

https://www.youtube.com/watch?v=MVm3LDWhXn0

Try to monitor Battery usage by iPhone Activity as shown below

What is shown under battery usage? Checking that would give you an indication of the usage behavior.

1. Background Activity
2. Notifications
3. Connected to Charger
4. Or any Other

Try some of these options too.

To prolong the life of your iPhone battery, you can follow these tips and best practices:

To prolong the life of your iPhone battery, you can follow these tips and best practices:

1. Optimize Battery Charging: Enable the "Optimized Battery Charging" feature on your iPhone. It helps reduce the wear on the battery by slowing down the battery aging process. You can find this option in Settings > Battery > Battery Health. About Optimized Battery Charging on your iPhone - Apple Support (IN)
2. Avoid Extreme Temperatures: Extreme temperatures, both hot and cold, can negatively impact your battery life. Avoid exposing your iPhone to excessive heat or cold, such as leaving it in direct sunlight or in a freezing car.If your iPhone or iPad gets too hot or too cold – Apple Support (UK)
3. Use Original Chargers and Cables: Always use Apple's original chargers and cables or certified third-party accessories. Low-quality chargers or cables can damage the battery and reduce its lifespan. Identify counterfeit or uncertified Lightning connector accessories - Apple Support (IN)
4. Avoid Draining the Battery to Zero: Charge it whenever the charge becomes lower than 20%. The rest is up to you when to charge. how long to charge, how often to charge, which adapter to use starting from 5W to 140W USB-C Power Adapter etc.
5. Optimize Display Settings: Adjust your display settings to optimize battery life. Lower the screen brightness, enable auto-brightness, and use shorter screen timeout durations. Adjust the display and text size on iPhone - Apple Support (IN)
6. Minimize Background App Refresh: Limit the number of apps allowed to refresh in the background. Go to Settings > General > Background App Refresh and disable it for apps that don't require real-time updates. Switch apps on your iPhone, iPad, or iPod touch - Apple Support (IN)