ios 15.2 battery drain

First all there will be a lot of housekeeping, re-indexing and photo curating going on after any update or after a transfer from another phone.

If you have iCloud photos turned on there will be a lot of Wi-Fi traffic.

There may be apps that are inherently incompatible with the new iOS

Start by removing any VPN or security apps. Apart from being totally unnecessary they are also a strong contender.

Many mainstream apps need an urgent update, so go to App Store and scan through your apps for those that need updating.

While there, uninstall any apps you haven't used for some time. They are unnecessary update burden. 

Check the battery usage chart in battery settings for any obvious bad apps but not every background process is shown.

Any streaming apps or apps that can run with phone closed, or Clocks that hold the phone unlocked, always force close them afterwards, despite the accepted wisdom not to.

Check Settings, Privacy, Location services and make sure none of them say Always. 

Check battery capacity is above 80% in Battery “health”. (yours is)

Only after all that do you need to do the simple stuff advised in

iPhone Battery and Performance - Apple Support

In extreme cases you can backup and restore to factory.

Battery Self-Discharge - User Tip

Check iphone battery for self discharge

Sorry, it's not helpful at all. I actually talked to Apple support, and ran the tests for them before my previous comment. They don't know how to fix the issue (even though they seem to be aware of it), and it's likely just yet another bad software update (not the first time).

If you were referring to having the phone turned off for a day after it was fully charged, and then checking the battery status after turning it on again, then it still shows 100% in my case without dropping at all.

You seem to keep making assumptions without any good rationale (and I am not sure for what purpose, to be honest; as I mentioned earlier, it's not super helpful, and your advice is sort of misleading instead), also ignoring the fact that exactly the same settings / apps worked fine not draining the battery for a long while till the latest update was installed. I understand that you are trying to help, but unfortunately you don't.

A lot of people reported this issue with the 15.2 update already, Apple is aware and their engineering team is investigating the issue. I got it confirmed by Apple's representatives. The issue doesn't affect all the phones, so if you are not experiencing the problem yourself, I am only happy for you, but it doesn't mean that the issue doesn't exist. It's not the first time when such things happen with iOS updates, earlier this year my wife had the same issue on her phone, while I didn't. She also reached out to Apple support and even visited an Apple Store that time, and it was also confirmed that it was an issue with a firmware / OS update, and she would need to wait for another fix; which she received in a couple of days, and the issue was fixed for her after that.

Not making assumptions, just that since these "xxx update killed my battery" have been reported since the forum started the liklihood is that it is your phone setup.

If you are sure it is the update then fine, 15.3 is in beta, not too many weeks to wait.

Good luck.

I’d be fascinated to know why you deem VPN apps to be “totally unnecessary”? I use mine every day, because a VPN is of enormous value to me. It’s not as if Apple is providing an identical service embedded within its own software. Please explain.

Corporate VPNs may well serve to keep company infrastructure safe. They are fine, usually.

App Store VPNs are an unknown risk. Heaven knows where the servers are and what they use your data for.

VPNs cause intold problems with payment and connectivity which you would know if you read the forum every day.

There is an Apple service called Private Relay with double hop privacy to give you all the security you might seek over and above iphones inbuilt security

Hello dear,

I am also using same model of iPhone and using heavy games App, Like PUBG. But never face this type of issue, so kindly check your model may be it has some internal issue.

Regards

[Link Edited by Moderator]

Much more likely to be what you have on the phone as my phone lasts all day answering these questions.

Same. After 15.2 update my phone became essentially not usable. The battery drains from 100% to 0% in 5-6 hours even when you are not using the phone at all.

See the post above yours, particularly the self-discharge test

Ah well, stick around for more helpful advice.

...out of interest post the result of the self-discharge test you did. If you really did one, the results will be available right now.

Good. Battery OK then.

It's your apps or settings and I gave plenty of suggestions to the original poster of the question what to look for.

15.2 does not have a problem.

Apple support confirmed that it't not a problem of hardware nor any kind of settings. It's a problem with an iOS 15.2 update, and they are aware of the issue.