iPhone 12 battery draining fast

That is not entirely how it works. A phone registers with an Update Location Request to a certain network element, after that it can roam freely in a certain area and the network will broadcast a short “call” to have to phone wake up and have it talk back. However, with two sims you still have to listen to two separate paging channels and that per definition is a bit more expensive in terms of resources. Having said that, my iPhone 11Pro also did that without such a battery hit. It seems to me there is a bug that keeps the phone in a very active state when two sims are enabled. I will try to collect some console logs to see if there is any indication in there what exactly is happening.

Exactly same issue here. First night, I had a 20% battery drain. Second night, 18% so I thought it could be a network thing so I reset network settings. The following day, my battery drained 10% overnight. That was the only improvement, if you can call it that.

I'm having the same issue with my phone - incredibly fast discharging. Had an Iphone X that would last all day, now by 1pm every day the battery is dead and it charges incredibly slowly if it's not plugged in. I have 5G and Cellular data turned off, no apps open, and it still can't last half a day. Called Apple and they said diagnostic was fine so have an appointment at the Apple Store. They said factory reset will hopefully solve the issue but I'm not confident

Ok so I ended up returning my unit yesterday and I was extremely surprised how amazing the battery performance of the replacement is. 0% battery drain overnight. Now, that’s the iPhone performance I grew up using. If I were you guys, have yours replaced.

same here. Dual sim excessive discharge. I suggest to call Apple support. We need more people reposting the issue. They are currently investigating my issue. At least they are taking it seriously as it got escalated to senior staff.

Your explanation is right to the point. This is exactly what’s happening and the issue must be the DSDS driver they use in iPhone 12 pro. Because the same sim setup worked flawless on iPhone 11 Pro as well as iPhone SE 2020. Hope everybody here follows the suggestions to submit feedback or call Apple support. My case got escalated and I’m hoping on a response from Apple next week.

factory reset etc. will not fix this issue. Thanks for your suggestions about the beta, if I don’t receive a satisfactory response from Apple I’ll submit the feedback through beta.

This is wrong. Please refrain from further comments as they do not help with the issue in this thread. The problem is the new DSDS driver on iPhone 12 pro. Probably also the regular 12 but I have no way of knowing. On iPhone 11 Pro etc. the same dual sim set up did not cause abnormal battery drain. A correctly functional dual sim standby does not cause double energy and battery consumption. If this would be the case there wouldn’t be any dual sim phone in use.

If you have only one sim in use I suspect you problem is different from the rest of us here. The funny thing is that my iPhone 12 pro consumes less battery when on a longer phone call compared to dual sim stand by mode. So clearly the issue can be pointed to the DSDS driver.

Hello all,

In my iPhone 12, I dont use dual sim but my phone is draining 20 to30% battery during night when it is idle in India when I take it to apple service centre the technicians not suggesting for replacement instead they want to reinstall the software in mobile.

kindly advice I m very much disappointed in buying apple 12

me too. Have an iPhone 12 single SIM and I’m loosing 15-25% every night while idle. BUT! last night I went into airplane mode and turned wifi off. See there I lost only 1% battery during the night. It has to be a problem with the Mobile data or SIM service. I’ll also report my issue to Apple. That’s a big thing

Every time I get home I turn wifi on and my data off! And still I’m loosing ~25% battery every night. Also I don’t like to charge my phone during night. I never did this on my iPhone 8 and I’m not gonna do this on my 12 either. The problem, I think, is just the sim service or something else with SIM. I went into airplane mode and lost 1% during night. I mean that can’t be a coincidence.

I’m also suffering from battery drain at night. I don’t plug in the charger over night and I’m loosing around 20% with no screen on time and all background updates disabled.

This last night my iPhone 12 lost 20% and during the exact same timespan my two year old Android only lost 2%. My wife’s iPhone SE (First Gen) also lost just 2% and she has background updates enabled plus a bunch of social media apps like Instagram and Facebook which I don’t have. 

Obviously there is something wrong, this drain is not acceptable. Nor is the suggested “fixes” like plugging in over night. I mean if it’s draining 20% during 6-8 hours, that’s around 60% a day compared to the normal which should be around 6% drain. This will definitely shorten the battery lifespan over time since you’ll waste more cycles because of this.

I updated to 14.2 but that did not make a difference. Not using dual-sim, just the e-sim. And 5G is disabled.

It’s similar for me. After charging to any percentage it seems to last abnormally long without any battery percentage decrease. After dropping the first % it seems to drop as normal according to use.

iPhone 12 only using single e-sim. Physical slot is empty.

This comparison is correct and is the same on mine. It’s a little annoying this dual sim problem. I got so frustrated I bought a pixel 4a to use with the second sim. But that’s not a long term solution for me.

I believe so as both sim use the same radio transceiver. That’s why it’s called dual standby. When you use one line the other gets temporary disabled. I figured that switching WIfi call, by switching off WiFi altogether would make a difference, but it didn’t. The bug must be somewhere else.