Level 2

158 points

iPhone 12 battery draining fast

Hi all,

Trying to work out if I have a defective unit I need to send back or if there's a wider issue here. The iPhone 12 Pro is advertised as having a smaller battery than the iPhone 11 Pro so I expected to have slightly reduced battery life (which is fine as 11 Pro was excellent).

However I'm noticing that the iPhone 12 Pro is draining when idle with almost no background activity at a rate of 4% which is much faster than my previous iPhone 11 Pro, and to be honest a faster idle drain than I can actually remember from a new iPhone. First instinct was to disable Mobile data to see if it was a 5G thing, but I actually don't see any real difference from doing that (which makes sense as I've been on Wifi 98% of the time since I got it).

No matter what I try, it seems to be going down oddly quick. Not to an useable level or anything world ending, but I guess its sort of suspicious. I check the battery report, and it's not showing any real culprit, just a rapid decline for no clear reason.

If anyone can share their idle battery with either 12 or 12 Pro I'd really appreciate it.

[Re-Titled by Moderator]

iPhone 12 Pro, iOS 14

Posted on Oct 25, 2020 8:14 AM

Top-ranking reply

user0197

Level 2

172 points

Posted on Jan 1, 2021 5:25 AM

After a couple days of experimenting.

Let me give you scenarios/examples with no regard to any other settings other than those mentioned being turned on or off.

iPhone 12 Pro running iOS 14.3

SIM card installed, WiFi on, Cellular On, Bluetooth in Standby (Turned off in CC to disable new connections, but still enabled)

Battery drops between 15 and 30% over an eight hour time frame while not being in use. (This was the case for a couple days, until I realized something was clearly wrong)

SIM card installed, WiFi off, Cellular off, Bluetooth standby same as before

Battery drops around 10% over the same time frame (Better, but still not satisfying)

Now get this!

SIM card taken out, Wifi on, Cellular off, Bluetooth same as before, I also turned Airplane Mode on for the sake of it

Draining between 1 and 3% , over the span of 8 hours.

I know, it seems absolutely silly to use an iPhone without a SIM card, but as long as this bug is not fixed taking out the Sim card might be your best option to prevent your battery from draining over night. Or you just simply keep it on a charger. Keeping the SIM and at least turning off WiFi and cellular or putting the device into airplane mode should make the battery drain a little less too.

Some other things you might want to switch off, if only to test for a couple days to see if battery life improves and slows the drain. Keep in mind, you can disable everything temporarily and don't have to worry about anything breaking. If something needs a certain thing enabled, iOS will most likely give you a prompt anyways. You can go back and enable everything again, but until a version of iOS 14.3.x or 14.4 is released that addresses the those kind of issues, it's the best and to be frank, the only thing you can do.

Location Services > System Services. Be bold and turn off EVERYTHING. Toggle the status bar icon (the switch on the very bottom) so when you slowly enable them one by one again, you can keep an eye on what triggers the location to update. With the status bar icon on, you can check and investigate closely how and when a certain service is updating. I found the Find my iPhone location feature updates like crazy.

System customization also updates in the background constantly ( if you turn it off, Dark Mode/ Appearance will still be able to work in sunset/sunrise mode, night mode however will work only when you put it on a custom schedule, and optimized battery charging will not work (even the option itself in the battery menu is enabled) if you have Significant Location and/or System Customization disabled).

Put Bluetooth into standby so it stops searching for new devices (Toggle it via Control Center so the icon becomes white.)

Turn off 'Ask to Join Networks' and set 'Auto-join Hotspot' to Never in Wi-Fi settings to stop the device from constantly checking for sources, notifying you and trying to connect to other routers.

I don't mention any of those things like turning off Background App refresh, dimming your display etc as those can be found in literary every 'iPhone battery savings' video or article.

It is clear that the issue can be pinpointed to the cellular modem, which can only be put into completely pause if there is no SIM card in the device. Airplane mode alone does not seem to fix the issue fully nor does turning off Cellular data help much if anything.

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Similar questions

2,818 replies

Nov 20, 2020 3:58 AM in response to Duli93

This is interesting. I changed my background to live again this morning and look at the battery curve. It started draining again. Constant drain 45° Downhill, now I turned it off, back to a still wallpaper and the battery acts normal again.

can it be that simple? 🤷🏼‍♂️

darrengf

Level 1

4 points

Nov 20, 2020 4:16 AM in response to Oliver S.

I’m also not using live wallpapers, never have,

I have a black screen, not even a coloured wallpaper,

but again live wallpapers won’t make a difference when the phone is in standby,

but it’s dropped another 4% in a hour on dual sim with esim as main one,

live not turned dual sim off and just using esim alone.

battery will now be happy

Nov 20, 2020 5:15 AM in response to Adds526

Me too - single line, physical SIM (O2 in the UK), no eSIM, and I am experiencing the power drain issue.

I can well believe that if there is a modem problem it will get worse if you have two SIMs in use, but the problem definitely exists even with a single physical SIM.

Nov 20, 2020 11:20 AM in response to CharlieNoah

Yeah, most likely it was just coincidence. Definitely the issue still persist is using dual sim. Using just the eSIM, battery is fine. ESIM is Telekom and physical sim is Vodafone. But it seems the issue is not as easy to locate as there are different issues in various scenarios.

however I believe it’s a bug in the modem or modem software causing the excessive battery drain. Let’s hope iOS 14.3 will contribute to a solution some have suggested.

Nov 20, 2020 4:25 PM in response to Lestat09

I don’t know WTF is going on. I previously reported after restore and using just one line (eSIM) the battery was normal, no more drain. This only lasted not even a week. Now the excessive battery drain in standby is back. About 5%/hour. Something must have triggered the battery drain.

this is starting to seriously **** me off. But it possibly explains the variety of behaviors that are reported here. It really must be the modem firmware, there is not other logical explanation.

C.Heise

Level 1

4 points

Nov 20, 2020 10:28 PM in response to Oliver S.

I also have this issue.

Using only one physical SIM in Germany (Telekom)

The last nights my battery drained in a range of 20-30%.

This night I used the Airplanemode with activated wifi.

the battery only lost 3%.

I hope there is coming a hotfix for this issue.

Lestat09

Level 1

13 points

Nov 21, 2020 2:00 PM in response to Oliver S.

So again, I did a clean restore on my Mac twice in a row. Guess what, battery still drains like ****! I am now happy and stress-free using my 11 Pro Max. I will go back to my 12 Pro when it’s stable already. Now it’s just on airplane mode.

Nov 22, 2020 1:36 AM in response to Master26A

Hi guys! I have also the same trouble with the battery and think I have solved this severe issue.

I try to change some settings on the iPhone and get a dramatic better effect of the battery.

The solution is the following:

Change every mail account to manual instead when it come for push or get action.

Change the setting in the app background refresh setting to turn off for Facebook and Messenger (if you have these apps of course)

This changes will dramatic improve the battery time in idle mode and you don't need to turn on low power mode anymore ☺️

Please, give me some reports here how the settings will affect you on the battery time? 😀

Have a nice day!

Nov 22, 2020 2:09 AM in response to Lestat09

Yes! They are maybe basic tips for saving battery life that you have heard of before.

But isn't better to have a good battery life with basic tips than a battery drained phone if this is the solution?

I wonder if all people here are using these battery saving tips before they have write in this thread? 🤔

Nov 22, 2020 11:11 AM in response to Lestat09

The problem is with the modem, which is why it goes away if you put the phone into airplane mode. All models of the 12 use the same modem, so they will all have the same problem. There are reports on this thread from owners of all the different 12s who have the same problem - I certainly do with my mini.

Apple need to acknowledge the problem, tell us if it is hardware or software that is causing it, and if and when it will be fixed.

Deptors

Level 1

9 points

Nov 22, 2020 11:16 PM in response to Dogcow-Moof

Try switching from LTE to 3G (if you don’t have 5G) I have the iPhone 12PRO after full discharge and charging (1A ) up to 100% holds 30 hours and my charge is now 67% (all services are enabled ... e-sim ), also I’ve disabled all the widgets ! One of the three actions helped ! Good luck 👍🏻 Attached last 30 hours

Nov 23, 2020 2:36 AM in response to Master26A

Ok guys...I have iPhone 12 and use dual sim. Last friday I turned off my e-sim and the batterydrain was 3-4% in idle mode over night. Yesterday before bedtime I activated my e-sim and this morning, as you can see, the drain was a fact! So, in my case the problem is running both sim at the same time. With this in my knowledge, is there a shortcut how to activate/deactivate my simcards?

Nov 23, 2020 6:17 AM in response to egorius90

That looks really bad and certainly is not normal. Apple support is no help at all at the moment.

I did a restore, clean install, using finder on mine. Set up as new and now the battery is fantastic. Look at the screenshot. Before it looked like yours even though quite frankly not as bad, more like a 45° constant drain.

But this fix for me only applies to using one sim, in my case eSIM Telekom Germany. As soon as I insert the second sim the battery drain is back. This is a serious firmware bug.

Nov 23, 2020 11:26 AM in response to Master26A

After reading some of the comments here I am pleased to see that other people are having the same issue (I'm not pleased FOR you but I'm pleased for me that I'm not the only one experiencing this!!). But my 12 Pro Max literally drains like 15% overnight and during the day, idle hours it loses around 2% per hour doing absolutely nothing!! Meanwhile my old 11 Pro Max loses less than 5% overnight and much more reasonable battery loss when idle during the day (i.e. barely anything). Both are running latest iOS 14.2 (14.2.1 in the case of the 12 Pro Max) and both are setup with the same apps, same configurations, same everything. Clones if you like...yet the older iPhone 11 Pro Max chugs along as it's always done. The 12 Pro Max meanwhile drains like a leaking pipe!

Deptors

Level 1

9 points

Nov 24, 2020 1:21 AM in response to Domjanlaci

By the method of exception, we have determined that this is a modem - higher than 3G network requires more power in standby mode to support the network, that's all, there are no other options and solutions ! The question is: is it a software bug ? If so, why does not everyone suffer from this problem ? Any ideas?

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iPhone 12 battery draining fast