iPhone 12 battery draining fast

Hi. I have been following this thread closely. I too have been experiencing this battery drain issue on idle whether during the day or through the night.

I tend to lose 15-20% during the day and maybe 8-15% at night (probably because i'm awake longer than i'm asleep).

What is interesting for me is my Wife has the exact same phone. Iphone 12 128GB (apart from the colour). I have a direct comparison. Her phone does not have the battery drain issue. Both phones have the equivalent settings, no background apps running, bluetooth turned off, location services very limited, the same widgets, the same apps.

The ONLY difference is that one phone is on the EE network, the other is on Vodaphone. Both phones have 5G disabled.

Now, I'm currently running some tests on my phone. I have done a hard reset, reset network settings, and for now, disabled mobile data, although I do still have wifi calling enabled. Having seen a lot of posts on here regarding dual SIM and then some networks possibly better than others, I have a feeling it is to do with how good the phone establishes a connection based on your carrier.

I am 2 hours into the test and from 100%, I have yet to lose even 1% on idle. I will report back if this fix works, obviously it is only temporary but with lockdown if you are at home at least it might help some people out from being concerned.

There’s one thing I noticed too RE sim. I have two lines: postpaid and prepaid. Simply put: when I use the prepaid sim there’s no drastic battery drain at all while using the postpaid sim drains the battery like crazy. Both same network.

I'm wondering about asking my network (O2 in the UK) for an eSIM to see if that fixes the problem. Has anyone else tried this? And has anyone who is using a single line with an eSIM seen the battery drain in that configuration?

Yes, I tested all scenarios with single SIM, eSIM and the combination of both. There does not seem to be a relation to this.

My best advice: wait for 14.3 to be released and see if this improves or fixes the situation. That's all I can suggest without getting banned here.

OK, so you are saying that an eSIM and a physical SIM on the same network both showed the same power drain?

In which case it can be concluded that the problem is specific to the network rather than a physical problem with the SIM itself.

I'm starting to get some battery drain in, 3 hours in. It's dropped to 98%. You are correct, I researched after your post and therefore having WiFi calling on is pointless because with mobile data off, regular phone network is still switched on.

If I turned Airplane mode on, I think this would be a fairer test. I will run the equivalent test with Airplane mode tomorrow instead of just turning off mobile data and report back.

I think having a phone with people unable to contact you via cellular is a bit pointless though :) It will at least prove it is a cellular issue.

No doubt, I’m just trying to make sense of it. Let’s assume in Western Europe is mostly Vodafone and in other regions most likely a different network. What also makes me wonder I feel there aren’t many US users complaining. Which would be odd as it’s the biggest market for iPhone. It can’t be the iPhone version either because I have the US version using it in Germany.

Had to check mine because I wondered if I just wasn’t paying as much attention to a possible issue like y’all are but I don’t have the type of drain any of you are mentioning. I’m still at 78% after moderate use and it hasn’t been charged since 12:45 am. I am on WiFi in a 5G area. I do not use the eSIM though. I have most things turned off in the background (carry over from previous device. I haven’t adjusted any settings on my 12 Pro Max yet). Perhaps I’m lucky 🤷🏽‍♀️

Very clear for me now! Yesterday my battery drained over 25% over night. I deactivated "mobile" and worked with Wifi-Calls and since then I have no more problems with the battery.

However, this is a workaround, but no solution. It must be related to the installed modems in the iPhone 12 and mobile phone connection. I use O2 in Germany. And it seems, that there's no problem with battery drain in the US.

Tonight the issue hit me again after a few good days. I used Shazam in the early evening and stopped using it. As you can see in the screenshot then suddenly during the night at 23:00 the battery started draining again, the only process causing this was Shazam for 100% or the time. What is particularly odd is that it stopped exactly around 08:00 when the iPhone fired it's alarm and took itself out of 'bedtime' and DND mode. Note: Shazam is configured not to allow background refresh and it was not 'killed' by swiping up. I had exactly the same issue a week ago when Siri was responsible for 100% of my background activity and also this stopped when the bedtime/DND mode was turned off.

How can we be and make sure that Apple knows about this issue and actively trying to fix it? It seems that the only place in the internet, where someone talks about poor iphone 12 idle because of the modem, is here. It does not make any difference if we just pity ourselves here and send apple out hopes and prayers. Does anyone know what is a process for Apple to acknowledge new issues?

This is normal. It will have some drain overnight. There is slightly less drain i think if your phone is on 100%. That first 1% seems to last longer. I also don't think its a great solution having phone on airplane mode in the house and then turning it back on when leaving.

I am having the same issue.

iPhone 12 pro max bought directly from Apple. Previously had an 11 pro max which worked flawlessly and had amazing battery.

I have two sims from different UK providers (EE eSIM and Vodafone SIM). I see an idle drain of ~20% overnight - battery shows nothing consuming this power..

Last night i removed the physical (vodafone) SIM and went to bed with teh device on 100% charge, woke up this morning with the device *still* on 100% charge.. which is the behaviour i used to get on my 11 pro max

I don't want a second phone for work, but I also don't want to have a constant drain on my battery when using a second SIM - it shouldn't be doing this..

Simply reporting it via the feedback form is NOT going to help you. You need to open a case via (preferable) telephone and insist on a senior advisor. You must make sure you break through the first line support who can only guide you through a few standard scripts. Senior advisors are able to talk to engineering.

My case is currently escalated to engineering, I get occasional requests back to provide new additional info etc.

I'm sure Apple is working on it, but the more people raise a case the more info they have and the better they can estimate the scope.

You´re right...did the same last night, airplane mode during the night ( 9 hours ) in the morning i had 100% full battery,no loss at all, rather than a 25% or 30% loss with only battery save mode on. But Apple has to fix this.