iPhone 12 abnormal battery drain / SHORT battery life

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Level 1

19 points

iPhone 12 abnormal battery drain / SHORT battery life

I bought iPhone 12 couple of weeks ago, and it didn't take me long to realize that the device is draining 20-30% each night (during a period of 7 hrs) on idle, which is very frustrating. I took it to the Genius Bar several days ago and the technicians there are perplexted and couldn't find the cause of the problem (no hardware issue). They offered a few suggestions (change a few settings) for me to test for the following days, and also offered to replace my device with a service unit, should the suggestions fail to solve the severe battery drain. I have been searching about this issue and found out that a lot of people (in USA, China and seemingly many other countries) are suffering from this excessive battery discharge issue with their brand new iPhone 12/12 Pro.

Below are some of the sugestive solutions I have collected, some of them given by Apple (non-working), and some of them given by iPhone users (some reported to be effective).

For the past few days I have been testing these solutions one by one night by night and here's what I got so far,

Turn off background app refresh (negligibly reduced battery drain)
Close all of the opened apps before sleep (negligibly reduced battery drain)
Update to IOS 14.2 (Not helpful)
Sign out iCould and sign in again (Not helpful)
Delete the built-in mail app (Not helpful)
Reset network settings (Not helpful)
Erase the iPhone and restore from a backup (Not helpful)
Charge the phone while sleeping (it's a workaround but NOT a fix)
Switch-off one of the two lines I'm using (will be tested today)
Use airplane mode before sleep (will be tested day after tmr)

Further, as you may already know, the battery graph shows nothing happened during the night (no apps no activity) and yet the battery drains 20-30 pct each night on idle.

In addition, I really don't think my iPhone 12's overal battery life is good enough, I am a LIGHT-moderate phone user, for example you may see from below last screenshot that I got a bit over 6 hours of screen-on time last Saturday and it consumed roughly 90 pct of battery, and that seems to be a best day for battery life efficiency, do you think it's nornal ? I think it is worse than the iPhone 11 and on-par with the iPhone SE 2020. So, I think, maybe the irregular battery drain of iPhone 12 consistantly exits during the whole day 24/7. And that is unacceptable.

Do let me know if you have the same issue or if you have found a workable solution.

iPhone 12, iOS 14

Posted on Nov 9, 2020 6:44 PM

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Answer 1

Top-ranking reply

dexefd

Level 1

4 points

Dec 10, 2020 8:09 AM in response to 炸弹黑

I only tested single sim unfortunately.

In the test, some of them drain about 1.5~2.5% per hour with absolutely no activity. Also, connecting to WIFI does not improve the situation. In comparison, the normal units only drain about 0.3% per hour. They are all using the same content transferred from a preconfigured backup. Finally, Popping out the SIM on faulty units IMMEDIATELY solve the battery problem.

Hope this helps

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Answer 2

Dec 25, 2020 4:07 AM in response to 炸弹黑

Hi

Guys after the third exchange from Apple find out this is not from the Iphone specialy my one is from the sim card.

I'm on O2 and during the night my battery was drain from 73% to 53%.

Last night i've put an EE sim card and battery gone from 71% to 68% which is significant change.

So in my case found the issue.

So i have to call O2 and find out what we have to do

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Answer 3

炸弹黑 Author

Level 1

19 points

Nov 12, 2020 7:25 PM in response to Deptors

Hi, thanks for your comment. My phone never has issue with background apps because I turned it off at the begining.

I use two physical sim cards, no esim, Turning off one of two lines did work. After turning off one line, the idle battery drain reduced to 6% for a period of nine hours, it used to be 18-28 percent battery drain during the same period of time.

But, like I said before, turning off the second line is not a permanent solution.

So today in the morning, I turned the second line back on, and force restarted my phone, I will test it for a day until tomorrow morning and determine if battery life improves after this force-restart. Below is how to do it:

Press and very quickly release the volume up button, followed by the volume down button.
Press and hold down the side button.
When the Apple logo appears, release the side button.

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Answer 4

Deptors

Level 1

9 points

Nov 14, 2020 3:55 AM in response to 炸弹黑

I have a physical card sim, I can also activate the second e-sim ! I have not activated it yet ! I have turned off the second call waiting ... at first I thought it was better (( but it didn't help to solve the problem !!!! The problem is definitely in the cellular network, this morning I removed the card from the slot ... for almost 5 hours, the charge is 100% I have apple must solve it as soon as possible !!!!

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Answer 5

炸弹黑 Author

Level 1

19 points

Dec 2, 2020 5:26 PM in response to YashG2406

I have been using only one SIM instead of dual SIM, and the battery life is fine since then.

For me and many other users I know, turning off one line is a temporary workaround.

I’m waiting and hoping the next iOS update could completely fix the issue.

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Answer 6

炸弹黑 Author

Level 1

19 points

Nov 10, 2020 5:58 PM in response to 炸弹黑

Yesterday morning I switched off one of the two lines I've been using, after a whole day it turns out that both the night time battery drain and overal battery life have improved. This seems to be a temporary relief but I can't keep the second line switched off forever. I know many iPhone 12 users who suffer from bad battery drain have found this method to be workable in reducing battery discharge. From this experiment and my previous experience, I do suspect my iPhone 12's ADDITIONAL battery discharge is within the range of 2-3% per hour with both lines turned on.

In my opinion, Apple needs to work out why this happens and FIX the problem with the next IOS update, before more users found out about their battery issues and start persuading their friends NOT to buy the iPhone 12 / 12Pro.

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Answer 7

炸弹黑 Author

Level 1

19 points

Dec 8, 2020 6:36 PM in response to dexefd

Hi there,

Thanks for your reply, can you tell me more about your testing done with a dozen units? In your tests, did you use one sim or dual Sim ?

In my case, my iPhone 12 battery drains fast only with DSDS (dual sim dual standby) mode activated.

So that’s why I have been using single line only since last month as a workaround.

Unfortunately I cannot return my unit and get refund here where I live, I am only allowed to have it replaced with a so called service unit in the apple store, I’m not convinced about the service unit, so I’m currently keeping my device and waiting for iOS 14.3 to solve the problem.

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Answer 8

sberman

Level 10

272,262 points

Nov 9, 2020 7:42 PM in response to 炸弹黑

You’re using WeChat a lot.

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Answer 9

炸弹黑 Author

Level 1

19 points

Nov 9, 2020 7:47 PM in response to sberman

Yes, but I don't use it at midnight and the phone is on idle.

Background app refresh is also turned off.

So I don't think it's wechat causing the problem.

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Answer 10

Deptors

Level 1

9 points

Nov 12, 2020 6:49 PM in response to 炸弹黑

Thank you for such detailed coverage of the problem ! Very useful ! And what does the second line ? When is the second call or e-sim? How does the phone behave now in the background ?

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