iPhone 12 battery draining fast

iPhone 12 Pro, iOS 14.3, physical SIM card.

It drains ~20-25% per night or ~3% per hour. This is in idle mode when no background app running, Siri off, analytics off, location services off and a lot of other settings off where possible (almost in brick mode).

I did a little experiment and ordered SIM cards from various carriers here in UK (EE, O2, Vodafone, 3). And I don’t see any difference. I’m experiencing the same level of battery drain in idle (and not idle) mode on all of them. No matter of signal strength. O2 provided the full signal strength yet the same level of battery drain was present.

All these are physical SIM cards. Earlier, I was able to somehow manage battery drain with eSIM on EE by using forced restart which could temporarily fix the drain. With physical SIM card nothing seems to help. Sometimes (but not always) it helps to set mobile data to 3G, but it’s not reliable.

Airplane mode always helps.

If next official update doesn’t fix this then it means that all iPhone 12 lineup is flawed and not fit for purpose.

Update to my previous post. iPhone 12 Mini battery woes have continued. Two nights ago I turned off all Background App Refresh and turned on Low Power Mode. As seen in the first picture it still lost 35% in 6 hours with zero use.

Last night I just left it alone and off the charger from 9:15 to 7:15. It lost 55%.

I am exchanging it today at Verizon for a new one. I hope it works! I’ll have two nights with it before I have send in my XR trade-in. I don’t want to let it go until I know the Mini is a go.

My cousin also has a 12 Mini, on T-Mobile, and reports excellent battery life. She did an experiment for me and left it off the charger for more than 12 hours. With at least an hour of use she lost 11%. So it’s only a subset of 12s this is affecting.

Update: Issue seems to be resolved

So after my 12 pro drained 25% during 6 hours in standby mode. I contacted Apple support who ran diagnostics. When the issue first happened my iOS version wasn’t updated as the phone was new. I updated to 14.3 and the issue seems to have been fixed

i did a test with my old XS Max, I charged both phone fully, both using a SIM with settings to LTE, WiFi on. I basically had identical settings on both phones in all aspects.

thankfully I woke up today and my 12 pro didn’t drain a single percent compared to the first night! I am so relieved but it is too early to say it won’t happen again.

It will not help everyone here but at least it will give hope... I think it is really not a hardware issue but a software one or even a bug of the modem.

Indeed I experienced it out of the box, a few days after when the phone had completed indexation to be precise, and I faced such drain on my 12 Pro Max :

Then I switch back to my 11 Pro Max which of course worked better. After one week, I went back to 12 Pro Max (each time from a finder back up) and now I get this which is more close to an "allowable" behavior knowing that the battery is smaller on 12 than on 11. Please not that I haven't adapt the settings, I don't turn anything off in comparison to my previous settings and I have 2 SIMs :

I truly think that the 12 (Pro Max) will never have the endurance of the 11 (Pro Max), I just hope it will stop to loose battery (even a single %) per night when in sleep mode with do not disturb activated ... as my 11 Pro Max did after a charge.

Here is how the 11 Pro Max with same setting BUT no SIM behaves in idle, we can see that after having fallen from 100%, there is a regular and constant battery use.

This is my battery usage compared to iPhone usage this night.

Using Low battery Power but wifi is on since it is stronger than the cellular.

it is a iphone12 mini about 1 1/2 month old. Think it happened after an ios update. It was not like this in the beginning.

hi

Will see from the screenshot that I charged the phone on friday at 3PM at 78%. I then switched to the physical EE Pay as you go Sim card.

The phone is behaving itself as if nothing is wrong.

You will notice that oin the 15th i was using the O2 Sim and battery was draining.

So yes, EE UK physical SIM card (prepaid) works fine in comparison to O2 UK sim. Here’s my screenshot. It shows a completely normal discharge graph after I inserted EE sim at 12 pm. No battery drain whatsoever.

As previously stated in this thread, EE seems to be the only network in UK without battery drain.

And btw, EE signal is a lot weaker than O2, still no battery drain.

EE signal 1-2 bars, O2 is 3-4. Weird. Must be something to do with network configuration.

Apple should fix modem software! I’ll have a chat with senior support agent about this tomorrow.

Further observations overnight. No draining.

Before going to sleep at 12 am, I enabled O2 eSim as a secondary voice line, but kept EE SIM card as a primary voice line and data. Looks good.

This is iPhone 12 Pro, iOS 14.3

For comparison, this is how my battery drains with O2 sim as a main voice and data line. Huge difference

hi ticuor

I am pleased to see that you are getting the exact same result as i am getting.

So it seems its either IOS 14 or the mobile network.

Can I just confirm again you had both SIMs active on the iphone simultaneously and still did not see any battery drain.

I switch to the O2 sim yesterday and again got the same result.

O2 SIM usage on the 17th

EE Sim Usage on the 16th

Hi

i kept the dual sim setup on my phone as well. My esim is with O2 and physical SIM card is pay as you go with EE.

Battery has been behaving itself all day. No drain at all overnight.

One other thing I have come across is that users who are evaluating iOS 14.4 beta are getting good results with their battery.

SOLUTION —PROB. FIXED

hello all I was reading about the problem a lot and I was having the same battery drain issue in 6-8 hours with lots of heating, and I did fix it and now the battery is staying for 2 days with heavy usage. HERE IS HOW TO FIX IT:

1- Go to settings >> Cellular

2- Select Cellular data options

3- Voice & Data

4- Select 5G Auto

Done ✅

see the attached photo and read what 5G On do to your battery life and it is the default selection I guess, so you need to change it and enjoy your full baterry life..

hope That this fixes your problem.

have a great day.

After installing the iOS 14.4 beta on my iPhone 12 Pro I left the device idle all night (background app refresh turned off, Bluetooth and wifi on) after charging it up to 100% and unplugging at 23:30. By 8:30 am the battery has dropped down to 84% which is a significant improvement to iOS 14.3 but doesn't completely solve the problem.

Here's a screengrab:

*Something I posted to another thread a week ago.

For everybody who would feel disconnected if they'd enabled airplane mode

While I am at home, I have airplane mode enabled all the time now (Wi-Fi is on constantly, Bluetooth only occasionally) and I have received every call and every text and am not compromised in any way. Please read.

A couple days ago I realized, even if airplane mode is on but Wi-Fi including Wi-Fi calling enabled, I can make/receive calls, send and receive non-imessage texts just normally. This is game changing. If this means I can just use my phone in airplane mode every time I am connected to Wi-Fi someplace, this is going to greatly improve battery life in every way. Because it means that the usual battery drain while having bad 1 bar cell reception in a certain spot in a building suddenly is eliminated. Granted there has to be Wi-Fi.

Here's a screenshot. Last charge to 100% was Saturday 8:30AM. Now it's Sunday midday and I am on 88%. I admit I don't have all too much screen-on time since yesterday however it was quite a lot of standby time. Considering that before, the phone would drain to 88% at the very least just sitting there idling over the course of 8 hours. No matter day or night. (I am saying 'no matter day or night' for all the people who insist everyone should charge their devices over night every night. Because the phone would drain on its own during the day just doing nothing as well.)

Also a thing I notice (especially on my iPad Pro) but that could just be placebo or something like that. If you drain your device to ~40/50% and then charge it back up, it usually has less standby drain and overall lasts a little bit longer as opposed to already charging it back up when it's only on 80%.

Also, I don't like Significant locations being turned on, which on the one hand bricks optimized battery charging for me but since I don't really have a steady charging/usage routine it would mostly likely not engage for me anyways, therefore it isn't a big deal because I plug in my phone when it drained around halfway or sometimes a little sooner, charge it, leave it plugged in sitting on one hundred percent for one hour max. If you unplug right when it reaches 100% it will mostly likely not sit on 100% for very long. (Apple devices are not fully charged by the time they display 100%. Depending on the device, charging it for an additional hour will make certain that the battery is in fact fully charged)

I am in no rush anymore because I am quite happy with the "workaround" as for now and this might be just the way I go from now on regardless of wether they fix the issue or not. Because I get better battery life that with every iPhone I had so far combined. And it's not too big a headache once you have simply integrated this procedure into daily life. (Granted, you need to have a contract that enables Wi-Fi calling for you to actually be able to utilize this). Turning on airplane mode when you get home and disabling it as soon as you disconnect from Wi-Fi (just like you maybe would go into Control Center to disable Wi-Fi when you head on out or disable Bluetooth when not needed anymore anyways), and all in all my battery lasts 4 days with ease doing it this way and like I said, its barely an inconvenience. I also got great battery life and no abnormal drain while on cellular data recently but you'll need to be in an area with great reception. (Recently, connected to LTE with 4 bars [I don't have 5G but I am on 5G Auto regardless, my phone sometimes manages to switch to 3G that way, it doesn't if I only select LTE], 20min of listening music streamed over Apple Music via Bluetooth in the car, 30min listening to music (wired headphones), some other minor things and in 2 hours I had lost exactly 1%!) I guess the issue is mainly there if the reception isn't 100% solid and the modem for some reason needs an awful amount of power, which most certainly seems like a software bug and that could be related to the carrier and how often a cell tower checks with your phone or how often the modem is set to update itself. Or maybe some carriers check more often than others, I don't know. Just speculation here!

[Edited by Moderator]

My 12 mini initially had serious standby battery drain issues. In the U.S., on Verizon. I tried different combinations of settings and nothing worked, but this week - without any update - it seems to have resolved. Starting Jan. 19 I took it off the charger at night and saw minimal drain, but daytime longevity has varied significantly, some days acting like a normal iPhone of this size and other days draining quickly. Yesterday the battery performed like a champ. As you can see here, I removed it from the charger at 12:37 am and 22.5 hours later at 10:58 PM it hit the 20% low power warning. While screen-on time of 4.3 hours isn’t great, that’s battery life I can certainly live with, and I hope this is the new normal for my mini.

btw the only changes I’ve made are to turn off Background App Refresh and I set it to full-time Dark Mode. 3g isn’t an option for me, so I initially set it to LTE-only but it defaulted back to 5G Auto and this was the result.

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.