iPhone 12 battery draining fast

In case you all haven’t tried this, I noticed my new iPhone 12 pro max draining battery like crazy and saw that the exposure notifications was on and running in background all night. This is something attached to the Covid-19 exposure. I also saw that my phone was testing noise around me for hearing exposure. I turned both off and my battery stopped draining while idle to a normal rate. Not sure if that’s your issue as well but it fixed mine!

Did you try to restore from finder on Mac, if you have a Mac? This fixed it for me. Everything else you’ve done I tried too with no success. I believe the clean installation of the uncontaminated software is crucial to eventually fix it. Again, for me this fixed it while everything else did not help.

I also point out that the DSDS modem was not fixed by the clean install. This is a firmware bug that can only be fixed by a new release from Apple. But I’m using just one line now, which works perfectly, no excessive battery drain.

IMPORTANT UPDATE:

I had the 4% idle drop per hour for 2 weeks on a 12 mini, but today I updated to iOS 14.3 beta, which also updated the modem firmware from 1.14 to 1.31. The draining seems to have stopped!

My phone consumed only 2.75% per hour in the last 8 hours, with 3,5 hours active usage! Consumed nothing when idle!

+1

It can lose up to 30% of its charge overnight.

At the same time, no programs were launched in the background.

Also, I gave about a week of time to index the system.

I've been experimenting for about three weeks now:

I did a hard reset first and set up the phone as new, but that didn't help.

Then, I turned off one function every night:

Unloaded all applications from memory - did not help.

Disabled background software update - did not help.

Disabled geolocation - did not help.

Disabled automatic updates of mail programs - did not help.

Disabled data transmission in the cellular network - it did not help.

Disconnected WiFi - did not help.

Today I left my phone with flight mode on and it worked. During the night, the phone did not lose one percent of its charge.

The phone is always in the same place - at home. I also did not observe problems with the loss of a network signal.

There is only one SIM card - physical (LTE)

TL;DR

iPhone 12 pro has massive battery drain with inserted SIM card. Without SIM card there is no battery drain.

I have the exact same issue. Battery drains about 25-30% every night, 3-4% per hour.

I also run some detailed analysis with some XCode Tools, showing normal CPU usage and nothing concerning.

So I tried to narrow it down: turned on flight mode, disabled 5G, turned on low power mode. Nothing changed!

Did several software resets with various method - no change.

One day I just did a factory reset and left it laying at home, so I took out the SIM card and used my old iPhone. Half day without touching and completely ignored, iPhone 12 Pro still had 98% battery left. So 2% drop in 12 hours instead of 3-4% per hour...

Thought I fixed it with that factory reset, so I set it back again to load the backup, swapped the SIM card back in and the problem was back...

So it's with the SIM card, no card -> no battery drain, with card massiv drain.

Getting it replaced now after 2 weeks of personal analysis, a cancelled replacement after 2 weeks and I now have to wait 4 weeks to get a new unit. Great.. 8 weeks for nothing.. but nevertheless a great iPhone, service not so much.

This is definitely a compatibility issue with some networks. I live in the UK and had a Vodafone Sim, thankfully I was due to switch my deal so I went with EE. When I was with Vodafone I had 15 to 30% drain each night and since being on EE I’ve had around 3%. I’ve noticed in this thread that other people that I’ve switch to EE in the UK I’ve also fixed their battery drain.

To answer your question, pls refer to my test done a week ago:

My battery drain issue (3-4% per hour on idle) happens only on dual SIM dual standby mode.

I tried to turn off the second line (CMCC) while keeping the first line on, and the problem is gone, idle battery drain at about 0.5% per hour, which is acceptable.

Another day I turned off the first line (SMCHK) while keeping the second line on, the idle battery drain was also 0.5% per hour, which is acceptable.

So it seems to me (at least in my case) that the problem may not be linked to “bad connections/incompatibility with certain carriers”, rather, it might be that the modem runs fast and furious when DSDS mode is on (because of unknown reason/bugs) and never rests. Just imagine, if you keep a car’s engine on 24/7, how many days/months/years will the engine last ? And of course, apple support (in some cases as reported) and a few guys here on this thread just keep suggesting that there’s “no problem” and we only need to constantly charge the phone (refuelling), how ridiculous.

Ok looks like I was able to fix the battery drain on iPhone 12 pro. When you disable background refresh not all apps turn off would suggest to manually turn off refresh for all apps especially WhatsApp and FB.

then under mail turn off push and set fetch to manual. I have seen a considerable improvement on battery..

Have you guys tried removing ALL the widgets from your screens, even those on the far left screen thats only for widgets?

I removed them all, and 2 nights in a row (no internet, NO airplane mode, low power mode on) my battery overnight drops with only 5-6%.

Last night I added the widgets again (again no internet, NO airplane mode, low power mode on), and the drain was like 25%...

I was experiencing the same thing on my 1 day old iPhone mini. I lost 35% of charge overnight. Then I limited my cellular connection to 3G/2G only. And it was much much better. I lost only 5% over the period of 8 hours.

Hi!

My iPhone 12 behaved in a similar way.

Discharged overnight by about 20% immediately after charging to 100%.

I noticed that all other things being equal, the discharge per night is about 5% if the smartphone was not connected to the charging. For example, from 45% the charge dropped to 40% overnight.

In the mail settings, push and automatic download were turned on, in which the iPhone checks the mail server automatically, provided it is connected to the Wi-Fi and to the charger.

Disabling push and switching to manual fetch to download new letters made it possible to completely eliminate battery discharge at night. This morning at 7:00 I saw 100% of the battery, charging ended at 2:20 (up to 100%). For almost 4 hours, the battery was not discharged at all.

Sorry for the machine translation into English.

here what i had done for my IPHONE

Turn Off Background App Refresh

However, allowing all your open apps to continually update and refresh in the background is a sure-fire way to drain your iPhone 12 Pro battery. To turn off Background App Refresh: ... Tap Background App Refresh. Hit Background App Refresh again, then select Off.

[Link Edited by Moderator]

Hi,

I’m using 12 Pro, with Airtel sim as well. I tried all the options you tried, nothing helped.

I even got a duplicate sim (a new Airtel sim), still nothing changed.

I read another member’s post in this forum who also uses Airtel sim. When they switched voice & data mode to 3G, the drain drastically reduced. I tried the same. It showed the result. I charged till 100% at night 11pm. Switched off only WiFi, and switched to 3G, you won’t believe, in the morning at 7AM, it was still at 100%

I know it’s not a solution, but temporary one.

My cousin uses 12 model, he says his battery drains only 5-6% overnight. His network is Vodafone. I also doubt it’s happening only with Ariel.

OOOH there is hope here guys! In absolute desperation I updated to the VERY LATEST iOS version (newer than 14.3 - have to word it like this so the post doesn't get deleted!) and my 12 Pro Max only lost 3% battery in an 8 hour period overnight (98% down to 95%!)...instead of the usual 15% it would lose in the same time period! I did notice that this update included a new modem firmware so fingers crossed this wasn't just a fluke...I'll monitor it for another day and report back! But I have hope now for the first time since I bought this phone! For the record I'm running a Vodafone UK single physical SIM (not an eSim) and I have been experiencing severe battery drain on ALL OS VERSIONS (including 14.3). This is the first time since I've had the phone that it lost LESS THAN 5% battery in an 8 hour period. I'll keep you guys posted!!!

FOR THE RECORD...I didn't turn on any low power mode rubbish, I didn't turn on Airplane mode either, the phone was on 4G (which is the fastest I can currently get in my area) and WiFi. Background app refresh wasn't disabled...so the phone was, for all intents and purposes, operating as you'd expect it to with no compromises!

Mobile data controls whether or not the phone will use a pure data connection over the cellular modem. It doesn't prevent the phone using voice over the cellular modem. If mobile data is disabled but the phone is still using 4G for voice and for periodic handshaking communications with the network, then the power drain (which appears to be due to the use of 4G and 5G on the Qualcomm modem) will persist.

Switching off mobile data does not turn off all cellular activity from the phone, and so does not fix the power drain. So it is disabling 4G and 5G which fixes the problem, not disabling mobile data.