iPhone 12 battery drain overnight

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.

My previous post was modified by Apple because I said that the battery drain problem was NOT the result of phone configuration. I should have said that despite configuring my phone to minimize battery usage, the rapid draining continued to occur, and required me to replace the phone. Users can reduce battery use by various means, but I experienced a problem with my battery that required hardware replacement, and the people posting here quite possibly may be facing the same issue. Hope this post is not deleted.

I don't know from where you guys are switching from 4g to 3g. iphone 12 doesn't have any 3g enabling options on its cellular menu. It only has 4G/LTE and 5G switching options depending on your carrier. some has 4g and 5g and some has LTE and 5G. which is by default set as 4G or LTE but in case off excessive use of internet you can toggle it to 5g. Furthermore data mode is by default set on Standard basis. which can also be change depending on situation you need. I think the area or carrier of your iphone doesn't has the ability of 5G yet. that's why you guys can toggle between 4g and 3g.

But I also have find some solution for me as I was very upset because of this from pas couple of weeks. After discussing and diagnosing this problem with apple care they suggest me to Restore my iphone from itunes. I did the same as they advised me So restore my cellphone with itunes after taking backup and I think finally I am relieved now. my battery percentage only dropping from 3 to 5 percent from last 3 nights consecutively. I turned of wifi with both sims are enabled (No flight mode) in one night and other night turning on Flight mode, only setting I change is I Enabled Low Power Mode and it working great now. I will update it if I face some problem again. But right now it is going good.

I have been using airplane mode for 5 nights now, I have WiFi and Bluetooth on so my phone isn’t completely disconnected. There is no drain with this settings and that is showing it must have to do with mobile modem in my case. Sins I have WiFi on my phone it isn’t disabled from internet and if it was a app that causes this drain it most likely would drain even in airplane mode with WiFi on.

I also have this problem and there is a longer thread about this elsewhere. Try not using bedtime mode if you use that. I noticed that the problem is very visible during the night and always starts at midnight and that happens to be when my bedtime mode activates. Tonight I tried activating bedtime mode earlier in the evening and the phenomena starts right away. A steep battery drain and Siri using 100% background.

jazzrabbit,

Just to be fair, I decided to NOT charge my phone while I slept last night. I didn't turn off Wifi. I didn't turn off Bluetooth. I simply let it sit on my nightstand in DND. My phone lost about 4% of it's charge from when I went to sleep in 7 hours.

If your phone is losing so much when you sleep, you've either got something running in the background which is doing that or you may have brought something over from your last Phone which is corrupt. You may have some setting not configured properly. This is by no means endemic to all iPhone 12 phones.

If I had your issue, I'd restore my phone to factory and NOT restore it from backup, but bring things over, such as Apps, photos, etc.,

I still stand by my recommendation to charge your phone when you sleep as a good practice and one which will preserve battery health long term.

Tonight I changed network setting. I use 5G auto instead of 4G, I set it on 4G because I don’t have a 5G contract and I thought it was the best setting for me. Tonight I only had 4% drain with everything on and it was almost 10 hour standby. I will keep trying this settings some days now.

Just turn on airplane mode

Did you update to IOS 14.4? Yes there was a software issue. But it seems to be resolved in IOS 14.4

This helped me:

1. Backup the iPhone using iTunes
2. Erase the phone (entirely)
3. Restore the iPhone from iTunes

Note: Save your photos before doing this.

I had to return the phone to Apple. It is a known problem.

12 pro, one sim ios 14.3. Sim card removed and no more drain overnight at all. left with 100% charged and awake with 100%. However, after 30min reading the news dropped down to 88, which is abnormal.

Try to set the phone to do not disturb, had a similar issue over the weekend and it was due to multiple notifications overnight, that keep putting the screen on, specially like a group chat or some similar

I think,i've a solution. Yesterday, just turned LTE to 3G and for the whole night ( about 8 hours ) the battery drops only with 5% I think this is OK,before that the battery drain even with cellular turned off was about 30 to 40%

2nd Update: I got my replacement 12 mini from Verizon on Saturday. Battery life during the day while setting it up was good, so I was hopeful. Oh, but when night came it dropped about 60% the first night and 48% the second night. So I threw in the towel and set up one of the many 5w chargers I have around to charge it all night.

Battery life today has been great - exceeding my hopes for the small mini. Off the charger at 100% at 7:22 am, and as of 9:12 pm after 14 hours of moderate use it's at 40%. That's comparable to my XR.

The replacement having the same problem tells me it's gotta be a software problem and not hardware, as it's unlikely an iPhone mailed to me from Verizon HQ and the one I got from the local store came from the same batch.

The replacement does have a better screen. The first one had very aggressive Tru Tone settings that shifted it so far to the warm side it looked more like Night Shift. The replacement has more neutral tones more consistent with the LCD Apple screens.