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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2,818 replies

progemix

Level 1

8 points

Nov 2, 2020 1:20 AM in response to Odiebla

Hey guys, I have the same issue as well. My battery loses 15% capacity over night. 5G is deactivated and still. I contacted the apple support, they analysed my iPhone 12 pro and everything they told me was that the iPhone is fine. If this is normal in their eyes, I will return the device. My previous phone was the samsung galxy s8 and it lost only 2-5% battery over night.

Nov 5, 2020 8:17 AM in response to Bobylov

How did you switch to 3G? I can only switch from 5G to LTE/4G, while latter is the only option available when using DUAL SIM and definitely makes no difference on mine. Still the same drain when using dual sim. When using only one line it's fine, whether it's in 5G Auto or LTE makes no difference, probably because it's mostly in LTE anyways. Also an important note this all happens while on WIFI too. No difference if using cellular data or WIFI.

Bobylov

Level 1

4 points

Nov 5, 2020 9:39 PM in response to Master26A

I've updated my iphone to iOS 14.2 and problem still present. After that i have called to apple support, they made remote diagnostics and told me that iPhone works fine lol. Their recommendation - "go to the service center and give your phone to diagnostics and repair". Nonsense.

Nov 5, 2020 11:58 PM in response to Master26A

Yes, a lot of iPhone users in China report that they have this issue too. Actually I have tried to contact with Apple support engineer. However, they just told me that my device looks good according to their test report and advised me to reset my phone or disable background refresh... Nothing works! I am so disappointed that there are a lot of people complaining this issue but what did Apple do? Just tell us a deadline when this issue will be solved, arrogant Apple!

Bobylov

Level 1

4 points

Nov 6, 2020 7:06 AM in response to Lestat09

i will make one experiment - my friend have iphone12 and no problems with battery drain, and i will test my phone with sim-card of his operator. may be this problem are specific to some kinds of 4G networks, and to some kinds are not.

Nov 6, 2020 10:11 PM in response to Master26A

Hello all,

In my iPhone 12, I dont use dual sim but my phone is draining 20 to30% battery during night when it is idle in India when I take it to apple service centre the technicians not suggesting for replacement instead they want to reinstall the software in mobile.

kindly advice I m very much disappointed in buying apple 12

bn766

Level 1

8 points

Nov 7, 2020 4:15 AM in response to zaagfluit

Your diagrams show something which i also found on my 12pro: After loading (it does not matter if up to 70, 80 or 100%) the iphone just needs roundabout 1% of battery in the first 2 hours. Thereafter the battery drain increases, so that my iphone needs 20 to 30 percent in standby while 6 to 8 hours in the night. I think there is a process which starts 2 hours after loading, but I have no idea which one it could be. My iphone is a dual-sim, but only the physical one is used.

Nov 7, 2020 5:31 AM in response to zaagfluit

This comparison is correct and is the same on mine. It’s a little annoying this dual sim problem. I got so frustrated I bought a pixel 4a to use with the second sim. But that’s not a long term solution for me.

Nov 10, 2020 1:22 PM in response to Master26A

I have the same issue. Apple support just told me to use the phone less or use low power mode.

The senior advisor told me to delete some apps...

next step will be to collect data and such.

I have an eSIM and wonder if that’s the issue? Either way it definitely looks like a software bug rather than hardware.

I hope this gets fixed soon because i can’t make it through the day without charging and I am not even doing anything crazy.

Lestat09

Level 1

13 points

Nov 10, 2020 4:41 PM in response to Odiebla

Yes I have the dual physical for HK. Last night I paired it with my series 6 watch and I was expecting a major drain since Bluetooth will be active all the time. This morning my phone's battery only lost 7%. Not what I expected but acceptable.

Nov 10, 2020 9:02 PM in response to Odiebla

Hey it seems things get mixed in this thread. Would it makes sense to start a new thread specifically pointing to our problem with the 12 battery drain issue when using two lines? I’m with you, there is most likely a problem with the DSDS module/firmware.

Nov 11, 2020 2:48 PM in response to Master26A

I have been experiencing the same thing with my 12 Pro. I have it at 93% before I go to sleep and when I wake up in the morning it drains down to below 50%. I tried swiping up all my apps, turning background app refresh off, and turning off precise locations and nothing is working. I too feel like it might be a defective battery issue as this has not happened to any of my previous iPhones.

Nov 12, 2020 5:27 AM in response to Master26A

Hi group,

I have exactly the same issue as all of you - terrible, absolutely terrible idle battery time

My Iphone 12 is literally discharging by its own in front of me without even doing anything on it.

I have the regular Iphone 12 64GB black, German operator - Deutsche Telecom, just 1SIM (no eSim). I always start with a clean install no backup restores and spend around a day to optimize it to the fullest.

Background apps are disabled, location settings stricktly limited to what needs to be used only, mail optimized, returned to LTE only (no 5G), no fitness tracking and bloatware like significant locations etc.

With all these settings and my phone calls my old Iphone X would get me around 3-4 days of casual usage before I need to charge it.

With the Iphone 12 now ......... only sitting there without even talking on the phone max is 1 day!!! I charge it in the night and it can barely survive with 20% battery till end of the same day. If I leave it overnight it would simply turn off and discharge the battery completely.

Apple please fix your mess immediately!

Below is a complete discharge for 1 day with just idling - 1 hour use to turn on the display and see how it is draining the battery .......

I tried no wi-fi, battery saver, DND mode ....... nothing works. Below is even visible this is battery life with battery saver turned on in the beginning.

If I enable 5G and start using my phone probably will need to walk with power bank.

Nov 12, 2020 9:56 AM in response to Odiebla

I have tried everything. Network setting reset, hard reset and ultimately the very last possibility a full restore using my Mac. Nothing helps, the battery drain is still excessive when using dual sim. Since my return window is already closed I’m stuck with it. Apple support is no help at all. This is annoying and I’m actually considering for the first time since 2007 buying a Pixel.

Nov 13, 2020 1:54 PM in response to Stephane73

I will try out the 14.3 beta and see if that fixes anything. If not, I will sell my phone and go to Android. Sorry, but Apple is no longer "just works." Their support is garbage, too. I wasted already way too much time troubleshooting this.

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iPhone 12 battery draining fast