iPhone 12 battery draining fast

I think what LostHopeI6 meant was in case of a recent update where the phone might drain faster because it is doing cleaning up etc in the background which uses more battery as usual. Actually, there is quite a lot of machine learning. Siri and Spotlight work closely together, constant monitoring what you are doing because they try to make suggestions based on what they think you need at a given time of day. Personally I think its kinda silly and turned most of those things off because I simply don't see the point of it. I also don't have a steady-enough routine like, for example checking mails every day at exactly 7:35 while sitting on the toilet so Siri would suggest the app on the lockscreen at exactly that time. Sounds silly, yes I agree but that is the idea behind it and how it works. If you don't specifically disable it for every app, your phone will monitor your usage wether it is able to pick up on your routine or not, which I think is just an additional battery hog.

This process is tedious especially if you have a ton of apps installed.

I disabled those options because I basically never use Spotlight search on my iPhone, so there is no need for it to constantly scan my entire device and look within every app I have installed to show me content.

For example, if you have 'Show content in search' enabled, and you type 'John' or whatever in Spotlight search, your phone will scan every application trying to find something that it thinks you could be looking for now. Contacts, messages, mails, Safari, pictures with linked faces, music etc etc etc. And in times this might be useful, but you could just as well go into the wanted application and search for what you are looking for, instead of having spotlight fully automated scan every last corner of your device.

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.

OK. With 14.4 and Siri Listening active my 12 Pro drained 25% over night. WIth Siri Listening OFF it drained 5%.

Before with 14.3 it drained 50% over night.

It would be fine if the 12 Pro would only drain 1–2% over night like my iPhone 11 Pro!!!! Apple!! (I already went through the Support with zero helpful solutions) :-)

I will try to explain it better with how my overnight drain is with different carrier and settings

Carrier A - voice and data set to 4G

Overnight drain with 0 activity - 20%

Carrier A - voice and data set to 3G

Overnight drain with 0 activity - 4%

Carrier B - no option of voice & data, shows up as LTE

Overnight drain with 0 activity - 4%

I am thinking the bug might be lying somewhere in these selections. I’d be happy to see if any users on EE and not seeing overnight drain can confirm they don’t see the Voice & Data under Cellular Data Options.

Problem solved atm, after upgrading 14.4 yesterday (with 14.3 - 15% overnight, after 24h only 55% left, same DoT)

26.01. 11PM - 100%

27.01. 07AM - 97%

27.01. 06PM - 91%

1hr45 DisplayOn Time

iOS 14.4

iPhone 12 Pro

no Airplane Mode

Mobile Data : 5G Auto

Data Mode: Allow More Data on 5G

Bluetooth and WiFi activated.

Telekom Germany, Physical Sim

Regards

Problem solved , after upgrading 14.4 yesterday

1:00 am - 96%

8:00 am - 96%

iOS 14.4

iPhone 12 Pro

no Airplane Mode

Mobile Data : 4G Auto

Data Mode: Allow More Data on 5G

Bluetooth and WIFI activated.

Sim active

Regards

Hedayat

Big improvement.

my original and replacement iPhone 12 Pro Max were loosing 20-30% overnight on iOS 14.2.1 & 14.3 no matter what I did. Eventually trying out things mentioned on this forum what worked for me was manually selecting 3G, then would have no battery loss overnight.

Upgraded to 14.4 yesterday. Overnight battery went from 91 to 88%. Which is more acceptable.

UK on O2 PAYG physical sim.

hardware model D54pAP

iPhone 12 Mini:

On the day Apple released 14.4 I was about to return the device including the Apple Watch and switch to Android after 8 years of iPhones. I had 20-25% overnight drain with 14.3, now it‘s down to 6% with 14.4. Still don‘t know where the 6% come from, but I can live with that. More importantly, I get about 7.5 hrs screen on time at home/via wifi (2 hrs Youtube App, 1 hr Safari browsing, 1.5 hr call via carrier, 1 hour amazon app, 1 hr messaging and mail, plus other stuff), and still have about 20% battery life left. Apple Watch was paired for about 10 hours, Airpods for 3 hours. That‘s rather ok or would you expect other results?

We are not complaining about 5G battery drain in this thread. It’s good old 4G.

I tested 4G and 5G capable sims on my iPhone 12 Pro. And as I mentioned multiple times, it drains constantly on O2, Vodafone and Three, with 5G off because prepaid plans do not even offer 5G here in UK. O2 has excellent full signal strength yet it drains my battery like crazy.

The only carrier which works for me is EE, no battery drain whatsoever, even with a weak signal (1-2 bars).

Some of the users experience battery drain on EE and not on O2. So it is the combination of software and hardware issues and depends on local carrier configuration.

Here’s how it looks with EE as primary line on 4G, no drain:

And this is O2, on 4G, same phone, same configuration:

I was just playing around a little in the Instruments application to see wether I can make out some process on the iPhone that is obviously running rogue. 12 Pro on 14.4

So far, the only things I did notice was, Wallet was continuously 'booted' into background mode and suspended again a couple minutes later. I never even use that App but have one generic debit card linked to it anyways. Disabling and 'deleting' Wallet completely through Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps > Wallet and then re-enabling it seems to have fixed that though. However I have not yet relinked the card.

Also Siri Search also always runs. Essentially every single time you simply swipe to the left or down from the Homescreen (Widget Panel/Search Field) and sometimes just randomly it seems. So every time you use Search on your device or check widgets on the left panel of the Home Screen, Siri is running. This would explain Siri showing up for people a lot in the usage graph even though they haven't used Siri itself (Ask Siri). Same goes with enabled Siri Suggestions on the Lockscreen or Homescreen etc. Keep in mind, I even have all Siri Suggestions off, Hey Siri disabled and all 'Learn from this app' and 'show content' etc settings from every app I have installed disabled, so technically Siri and Search virtually should have been turned off for the most part and no constant indexing of every app should take place. Unless it happens in the background no matter what switches you have disabled.

Anytime you have only one bar of cellular reception your battery is going to drain significantly. There is also no need to disable Wi-Fi overnight as it uses very little power. It is even better to leave it on if you have the option or already have enabled Wi-Fi calling as this reduces the back and forth the cell modem has to do with the tower and instead does all that through your home Wi-Fi's internet. Same as GPS, as long as you have no apps that have their location update set to 'always' instead of 'while using' or 'never' there isn't really that much activity there that could be causing any significant drain. You can/should however disable Bluetooth when not in use.

Low Power Mode also has very little effect while your device is in standby as it is more aimed towards throttling and reducing CPU activity and other things while the phone is actually in use.

Apple asked me to take my phone at the local Apple service and they will either repair or replace the device. The Apple support girl told me that the engineers found a hardware problem in my device during the remote checks they were doing. I think Apple’s behavior is really bad not publicly announcing an acknowledgment of the problem and either replacing or fixing the phones on their own expense.

Note: Since 14.4 I’ve noticed that the drain occurs overnight only when my phone has battery or below 50%.

it's a software problem 100%, older iPhones with iOS 14 don't have drain issues.

I fixed this issue on my iPhone 12 with update to iOS 14.4 - drain is dropped to 1-3% during the night.

Also, I found this options, you can test to on/off it:

General - Mobile data - Mobile Data Option - Low data Mode (Turn it ON)

If you have eSIM and using 5G:

Settings - Cellular - Cellular data options - Voice & Data - Select 5G Auto

Check it overnight.

leave it as normal one night and check battery drain

next night put it into flight mode

if battery drain almost stops then it is not a battery problem

contact Apple support and keep on at them

had similar issue with 2 new iphone 12pro. IOS14.4 fixed it for both

I have been able to establish beyond doubt that the battery drain on my dual-SIM iPhone 12 Pro was entirely due to my eSIM. Taking the physical SIM out didn't help, but eliminating the eSIM produced this result - almost zero drain overnight: