iPhone 12 battery draining fast

After reading some of the comments here I am pleased to see that other people are having the same issue (I'm not pleased FOR you but I'm pleased for me that I'm not the only one experiencing this!!). But my 12 Pro Max literally drains like 15% overnight and during the day, idle hours it loses around 2% per hour doing absolutely nothing!! Meanwhile my old 11 Pro Max loses less than 5% overnight and much more reasonable battery loss when idle during the day (i.e. barely anything). Both are running latest iOS 14.2 (14.2.1 in the case of the 12 Pro Max) and both are setup with the same apps, same configurations, same everything. Clones if you like...yet the older iPhone 11 Pro Max chugs along as it's always done. The 12 Pro Max meanwhile drains like a leaking pipe!

iOS 14.2 doesn’t fix this issue for me.

iOS 14.2.1 doesn’t fix this issue for me.

I can only wish and hope that 14.3 can fix it.

If it is really a modem related issue like many have mentioned here, can it actually be fixed simply with iOS updates ?

Anyway.... in my case the abnormal battery drain happens only when both SIMs are activated.

BUT, even though I’m only using one SIM card now as a workaround, I still kind of feel like my iPhone 12’s battery life is not ideal, maybe worse than that of iPhone 11 and the previous XS max.

Can someone WITHOUT abnormal battery drain issue tell us, how is your iPhone 12/12mini/Pro/Pro Max’s battery life ? How may hours of screen on time do you get ?

Right, I've given up on all the non-drastic solutions. I've just done a full DFU restore to vanilla 14.2.1 on my 12 mini, and not set up from my backup; set the phone up as brand new and only loaded a few apps back on. I'll use the phone like this for a day or so and see if it has made any difference.

Some people are not seeing this problem and are getting good battery life from their 12, but there is clearly something not right somewhere, or there wouldn't be 33 pages of unhappy people on here! Having tried everything else I can think of, the only remaining thing that might explain it is some setting in the backup I installed from my old SE which is triggering the battery drain; setting up a phone as new without the backup is unbelievably tedious, but if this doesn't work, this phone is going back for a refund until Apple address the problem.

By the method of exception, we have determined that this is a modem - higher than 3G network requires more power in standby mode to support the network, that's all, there are no other options and solutions ! The question is: is it a software bug ? If so, why does not everyone suffer from this problem ? Any ideas?

om On 14.2.1 have discussed with Apple support who say the device is fine despite it losing 15-30% per night. 15 percent last night on 24th November. I don’t have 5g enabled as I don’t have coverage here and I only use 1 sim. I have done a full restore twice from iTunes on Mac and it hasn’t fixed the battery drain. I have never had an iPhone drain so much to quick on standby. I have minimal apps installed without background refresh. Apple support have been no help unfortunately. I will be leaving iPhone next year if Apple don’t do something about this.

this is fucked. I just did another fresh restore last night and setup as new. Phone is even draining faster than usual when in use (over 4G...I dare not think how bad it will be on 5G!!). Compared to the old 11 Pro Max which managed to squeeze 3 hours of screen on time before it hit 90% yesterday (which is unbelievably good!) the 12 Pro Max managed just half an hour.

Yes, I just got something in my mind. There are 2 possibilities, which are very likely:

1. There are 2 4G/5G cell towers, which are on similar distance from the phone. If there is actual problem with locking to a specific tower, it constantly changes the tower which leads to battery drain.

2. There isn't a 4G/5G cell tower in close range, which also can lead to battery drain.

If it is the first one, I believe that it can be fixed by a software update. For the second one - I'm not sure. We need someone from Apple to acknowledge the issue, which is 100% there.

in Hungary, we have great 4G/LTE coverage, the second issue is not a root cause. Apple simply changed to Qualcomm modems and it seems iOS can't handle them properly. We can only hope it's not a hardware issue.

OK, at 7 this morning I did a full DFU restore on my 12 mini and set it up as a new phone with nothing from my old backup. I have installed 10 or 12 applications from scratch, all of which ran quite happily on my SE and did not cause power drain. And I am still, 4 hours later, seeing the same rate of power drain as previously.

I'm giving up on this phone - mine is going back for a refund. I'm starting to think that those of us who are seeing this problem have modem chips which have a hardware fault; I've now tried everything I can think of to fix this through software. If Apple address this in future, I might buy another 12 mini in 6 months time, when they have fixed the bugs, but for now, this is not fit for purpose.

I couldn’t agree more !

OK, at 7 this morning I did a full DFU restore on my 12 mini and set it up as a new phone with nothing from my old backup. I have installed 10 or 12 applications from scratch, all of which ran quite happily on my SE and did not cause power drain. And I am still, 4 hours later, seeing the same rate of power drain as previously.

I'm giving up on this phone - mine is going back for a refund. I'm starting to think that those of us who are seeing this problem have modem chips which have a hardware fault; I've now tried everything I can think of to fix this through software. If Apple address this in future, I might buy another 12 mini in 6 months time, when they have fixed the bugs, but for now, this is not fit for purpose.

Ok so after 3 days, my 12 Pro Max is now experiencing the battery drain mode. This is my 3rd iPhone 12 already all of which suffered from this insidious disease. It cannot be a hardware issue. I mean, how unlucky I must be.

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.

Now that's very interesting. I'd wondered if it might actually be that some SIMs have a compatibility problem with the modem; your post suggests that this problem is network-specific, so it may be that some networks need to update their profiles to work properly with the modem in the 12. I had considered asking O2 for a replacement SIM or an eSIM to see if that made any difference - maybe I should do that before I give up and give the phone back...

So I’m having the exact same issue; approx 4-5% per hour drain overnight. I’m on my second device from Apple but was able to keep the original device and have been testing a few things out (nothing has solved it but there’s been some interesting quirks). Both devices have the exact same issue and it’s consistently repeatable day after day. I tried restoring from back up, setting up as new, unpairing watch etc. But no improvement.

Im running one sim (physical), I’m on the O2 network in the UK

On receiving the 2nd phone, I removed my sim from the old phone and put it in the new, but left the old phone set up on my account (just to rule out the watch theory, my watch was still linked to the old device for now). The following morning, with the original phone left idle since around 12PM, it was still in the mid 90’s, while my new phone had depleted to 60% and had been off charge for 12 hours less.

I then wiped the original device, but set it up for one of my family members, including using their sim, to see how that went. I charged it to 100% at 3 in the afternoon. The following morning, with a small amount of usage (around 45 mins) throughout the previous evening, the phone was now at 93%

This is obviously in line with what I would expect from a perfectly working phone...

What really gets me is; the different sim I was using was a Tesco sim, Tesco use the same network in the UK as O2, yet one seems to be causing horrific battery drain and the other doesn’t.

Appreciate that this is not unique to my network around the world but I thought this was interesting to say the least!

This is interesting and also something I had considered. Now which network drains and which doesn’t. The reason why I have no problems with my Telekom eSIM (EE is part owned by Telekom) while adding the Vodafone Italia sim the drain starts. So either a dual sim problem or perhaps really a network problem? It might be the most logical explanation other then a firmware bug.

I’m sure though that turning off data will jot make a difference. It’s has nothing to do with data, it’s the connection to cell operator itself even without data. I tried this by turning off roaming for my Vodafone Italia sim with no change in battery drain.