iPhone 12 battery draining fast

I have the exact same problem as everybody else. It's just that I have found the workaround. And I haven't even checked wether the drain would reappear again because my device behaves completely normal the way I have it set up right now. Overnight drain is 0-2% max.

It does only work with Wi-Fi Calling unfortunately (I don't know if you have it, because I remember we already talked about it right? But sadly I forgot wether you have it or not) So if you don't have the option, you may ignore the following.

Since I would go into Settings and disable Wi-Fi completely and manually every single time I leave the house or leave any place with Wi-Fi, I have made myself a shortcut that primarily includes two modes. Indoor Mode and Outdoor Mode that I can access quickly with only one swipe and a tap.

With Indoor Mode: Airplane mode engages, Wi-Fi turns on, Bluetooth turns off, Cellular Data turns off (naturally done with airplane mode).

Outdoor Mode: Airplane Mode turns off, Wi-Fi turns off, Bluetooth stays off, Cellular Data turns on.

So instead of manually disabling Wi-Fi in Settings (not Control Center, as it does not disable Wi-Fi entirely), like I would do regardless when I go out, I simply switch modes. You can take this further by allowing Shortcuts to use your location and enable a mode when you are leaving a place (home, work) etc. However I did not do that since it again would require a location service to run all the time. And as mentioned, I made it a habit to manually disabling Wi-Fi, so its not really an inconvenience for me if instead going into Settings, to swipe to the widgets screen (or wherever you want to place that widget) and manage it from there.

I also made a Bluetooth Toggle which allows me to fully switch off Bluetooth without going into Settings and a Cellular Data toggle so I can switch it off right there as well if I choose to do so.

I unplugged my iPhone at 13:40 today and at 23:00 it is still at 100%. Don't mind that I have barely used it. Imagine the entire time span to be 'overnight'.

I don't know if it did anything, but you can also try the following. Go into Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps and turn off Wallet. Restart your device and then go back and re-enable it. You will have to add your cards again if you have any.

*I monitored my iPhones activity with a Xcode program recently and found a glitch where a 'Wallet' process was constantly reloaded, ran for a while and was then suspended into background again. Ever since I disabled it, it did not recur again.

I could not go to store as closed due to covid. I had suggestions such as restore to factory etc, and apple even sent me a new phone but no different. Only IOS 14.4 fixed it . Im an engineer so understand your frustration. All you can do is take phone back and demand a refund or keep on at support and get through to senior support and insist they pass it up to engineering. Issue is related to carrier settings and modem , where phone seems to use too much time and power talking to local phone masts. You can prove this by putting phone in flight mode when battery will lose very little overnight. The fact that one SIM( one carrier) is OK and the other not OK proves it.

Recall not required, problem is NOT hardware or battery related. Seems to be excessive communication to phone cell by basic phone communications ( not mobile data) as no problem if in flight mode. Issue with my phone was fixed by an IOS update, but still not fixed for everyone and all carriers

make sure you have latest IOS and if problems persist call Apple support and insist on speaking to a senior representative .

Some ( a few) have had severe battery drain issues, it is NOT a battery or hardware fault, as fixed by IOS or carrier update. Apple are not admitting it.

leave your phone overnight on flight mode, battery should not drop more than one or two percent. Then try overnight flight mode OFF, wifi on, battery will drain more but still a few percent. If it drains say 10-15 percent then you have the issue, call apple support and dont give up until fixed.

I’ve been back to the store and had all the checks and a reset. After that all was well until I reinstalled my Huawei fitness band app. Battery drained 60% overnight. Uninstalled it. No more problems in last 3 weeks. Looks like that was the issue.

This sounds same issue i and others have or had.

no battery drain with flight mode on, 15-25% overnight if flight mode off.

It seems to be a problem with phone communications to cell mast ( not mobile data) as some users found changing SIM to another network fixed it. I actually got a replacement phone from Apple which had the same problem. It was fixed for me by IOS update 14,2 to 14.3 and thankfully has been good since .

now overnight battery drops about 3-4%

i suggest you contact Apple support and insist on elevating the case right up to highest level and to Apple engineering

A little late reply but here is what happened, as suspected there was nothing changed on my providers end.

Apple send me to an Apple store to check my SIM slot and antennas and everything was okay.

I was still in contact with Apple support and they finally pulled all the log files from my phone and the engineers looked at it and discovered there was an hardware fault. ( They couldn't tell which hardware part was at fault..)

There next step was to send it for repair again, with specific instructions on what to repair. But UPS screwed up again by not sending an email when they would pickup and they didn't bring any packaging (as told by my wife).

So I contacted apple again and because the repair would probably fail anyway because it is such a specific repair they offered me a new phone.

So I had to send my phone to them and they send me new one, and luckily the new one is working perfect.

So all in all, after 3 months I finally have a normal functioning phone.

For what it is worth, Apple at least sees it as an hardware fault. So if you still have the same problem, ask them to get the full log files and let them check it by the engineers.

That is simply not true, I'm an engineer working in the mobile telecom industry and the discharge rate currently seen on my iPhone12 is a faulty curve. I feel no point in debating that, as this is just a simple scientific observation that I already cross-referenced with a known-to-be-good situation both both the iPhone11 and the iPhone12 under normal conditions.

Please check both curves, on the top you can see a drain, regardless of any handset usage during day OR night AND despite low-power mode. Any engineer can tell you this is abnormal behaviour. On the bottom you will see a 'normal' discharge curve, where you can clearly see it's not a straight line down the hill but is depending on usage etc. Note: both are made on my iPhone12Pro, the bottom one differs in 1) no second 5G SIM (in 4G mode only) enabled and 2) low data mode mode enabled on the first primary eSIM. I'm currently testing to see what actually caused the difference in discharging by disabling low data mode on the first eSIM. If the discharge rate continues to be 'normal' then there is a clear indication that enabling the second SIM caused abnormal behaviour. That is not 'me too', that is just a normal observation. If you think it's normal then you're perfectly entitled to that opinion, but then there is little you can contribute in this topic I'm afraid. It is my personal and professional opinion that this is not normal and considering the fact that Apple has accepted bug reports, fixed the issue and contributed them to me in the release notes I think I'm still doing a useful job here :-)

NittyMDev wrote:

Adding few bits from my experience thus far.

Device: iPhone 12 128GB

Location: India

Physical SIM provider: Airtel

eSIM Provider: Airtel

I have read much possible comments on this post - over a period of time. Have been following this thread for long now, even before it was picked up by Forbes.

All I got to say is based on my own experience and experimentation to validate some of the recommendations provided here by other users. This is not the desired state in which I wish to operate my device!

I "believe" (like many others) it relates to "modem firmware", and I do agree with the statement "that's not why I purchased this device" as many have stated. Also this may not even be a workaround for regions where there is only 4G / 5G+4G OR with individuals who would majorly be on Mobile Data for communications.

Okay, with all that said, ONLY state in which the battery usage is what could be called "Normal / Acceptable" - as per my experience, is with 3G selected for Voice & Data. This is an "okay" state for me as long as I am on Home WiFi, with WiFi calling enabled. The moment I step out and enable 4G, I get back to "Ground Zero".

What I am more curious is to see if  addresses this in future update for Modem Firmware.

Until then, I'm just dropping this post here, along with screenshots.

https://discussions.apple.com/content/attachment/de6b5cb9-f817-45bf-96a9-98875a49ce04

https://discussions.apple.com/content/attachment/6da7550b-d92b-450a-97a5-3b719be4885f

https://discussions.apple.com/content/attachment/6da7550b-d92b-450a-97a5-3b719be4885f

Alright, here for an update on my experience thus far.

Following other discussions after my last post, I came across the post by @oli1605 which mentioned of possible issue with Physical SIM connection. His logs made sense to me as well, as I keep getting these intermittent full screen notifications, for sending carrier message (generally sent for network registration) on my Physical SIM only.

So, all I did was set my eSIM back on 4G and my Physical SIM on 3G, having both Data Roaming and Mobile Data Switching enabled. Results thereafter were much better!!

This again, is not an option for regions / network / users where 3G is not available but Only 5G / 4G.

Try setting both SIM on different mode for Voice & Data; I am not sure of 5G / 4G, but 4G / 3G setting is definitely working for me.

Here are my results.

Charged to 100%

Charged to 84%

For the level of crazy drain I was experiencing earlier i.e. ~20% to 30% on 14.2.1 and ~12% to 18% on 14.3 during idle - in about 6-7 hours, with

Voice & Data set to 4G on both lines

+

WiFi / Bluetooth / Mobile Data turned off,

this is a Much Better!!!

Current idle drain is just about 2% to 3% 🙂

Unfortunately the situation has indeed not improved with 14.2. I strongly encourage everyone to submit feedback to Apple. The best way to do this is by using the Feedback app. You can enable this by enrolling in the beta program and install a beta profile on your phone. After rebooting you will have a new 'feedback' app (you do NOT need to actually install a beta!) and here you can create feedback. Answer all questions, include screenshots of the drain and include diagnostic files for analysis by Apple.

I'm pretty convinced there is a bug in the new radio/DSDS (dual SIM, dual Standby) driver/firmware that is triggered when two SIMs are enabled, it seems that the phone then continuously burns a lot of cpu time and eats away battery at a linear rate without any justification for that.

To all guys who are suffering from this issue:

The experimental result on last night indicates that the battery standby curve of my iPhone 12 is now back to normal. I will share the solution in the following. First, you should reset your network settings. After that, the most critical step is that you must set the default voice line the same as cellar data. Now your iPhone should have the normal battery standby curve. I think it's a potential bug in iOS and I have report to Apple. Tell me if this solution works on your iPhone.

Ok. I think my issue has been resolved. At 5pm yesterday I reset the network settings. I went to sleep at 8:30pm and my battery was at 59%. Woke up 5:30am and it's now at 57%. Now that's the iPhone standby battery time I've known for so long. 0-2% battery drain on 8-hour idle. I hope it's going to be consistent.

I tried all the things on your list with the same experience (except point 7, I only use nano-sim). Now I tried the complete reset and install everything new, not from my backup. This seems to help. Until now I did not install any additional apps. My iPhone needed 13% of battery power in more than 16 hours in nearly standby. It will be interesting what happens when I install allthe apps I need.

After 4 days of experiencing normal battery behavior, I can now confidently say that resetting the network settings truly resolved my battery drain issue.

Since resetting the network, battery on idle overnight has been like this and I’m talking about 8-12 hours of standby:

Night 1 - 2%

Night 2 - 3%

Night 3 - 7%

Night 4 - 4%

I have been experimenting all day with different settings. I see no problem if I deactivate one of the SIM cards.

If I set the physical SIM card as the default data SIM, no problem. Normal idle battery consumption, around 0,5% per hour.

But if I set my eSIM as the default data SIM then the phone starts to idle with 4-5% per hour in battery consumption.

Feel free to try it too and see if you notice the same thing.