iPhone 12 battery draining fast

Yes it is. in my case, my phone uses

7% overnight (8 hours) With only physical sim and 35% with the e-sim also enabled. And this is the case with more users in this discussion. And for the record, all iPhone 12 models are dual sim capable.

All US+EU models do not support 2 physical cards, so unless you bought the unit in Asia this is not even an option to you. Having said that, it would surprise me if the usage of eSIM causes the problem.

7% overnight is in the NORMAL RANGE. If it bothers you that your phone is working as designed get rid of it and get a basic flip phone that will go for a week on a charge. Or follow the best practice of charging the phone overnight, which is better for the battery as well as keeping Wi-Fi on.

Agreed. I was responding to the 7%. For the 35% with 2 lines, what is the signal strength on each line? Cellular data and voice adjust power output based on the signal strength of the network access point. With 5 bars the phone can maintain a connection with 50 mw transmitter power. For 1 bar that goes up to 600 mw. And, if the phone is not plugged in, all data updates overnight use cellular data. And if you have 2 lines active the power required for the cellular connections is additive.

And the solution is still to charge the phone overnight.

anything up to 10% overnight would be more than acceptable, I think my iPhone11Pro lost less than 15% overnight. The problem with the DSDS bug (which it seems) is that I'm loosing up to 35 to 40% overnight in complete idle mode.

And I've said it before: some of us (me included) don't like to have a lithium battery charging next to their bed. It's a risk, it's a small risk but it's a risk I'm not willing to take. Also, on more than one occasion I'm not able to charge overnight for a variety of reasons. With a loss of 7 to 10% overnight that is no problem, but just loosing 40% overnight and the same (but often more) during an 8 hour working day cuts the battery life too short.

Today I had a call with Apple Tech support 2nd level and they acknowledge they reveived more complaints about this and they are collecting data. They did the same with me and are sending it to engineering for review. The unit (again) has been diagnosed to be operating fine from a hardware perspective so currently they are focussing on the software side, which to me sounded promising. I will do additional tests and send these in for them to add to the case and I strongly recommend everyone (especially if you, like me, loose around 35% per night or more with dual-SIM when single-SIM operation is fine) to raise a case and insist to have it send to 2nd level who seemingly is aware of the current complaints. Providing feedback will help, just stating that you should charge overnight is a work-around for some but will not fix things.

I have 'less than ideal' reception here on the eSIM and indeed this may have a battery hit, but not to this extend. And also, why does that battery-hit then disappear when disabling the second SIM (which has full reception)? Also, why does the 11Pro perform perfect under equal config and conditions?

For me everything still points towards a bug in the radio driver that prevents the device from entering idle mode when in DSDS config.

Really? This fixed it? My cellular data has been the same as default voice line. So I’ll try to reset network settings. In my case this might make sense as I’ve transferred from my former iPhone instead of setting up as new. Is your battery still behaving normal?

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.

Yes. I used two physical sims(China Mobile and China Unicom). The day before last night, I set the default voice line and cellular data to China Mobile and the battery curve is back to normal. But last night, I set both to China Unicom, this issue occurs again. So I doubt that it is related with operator.

I am also facing the same issue with my iPhone 12 pro. First I thought i might be using my phone way more than usual but it’s still persistent when I’m not using my phone at all. This is a bit disappointing when this happens to a brand new phone and I have never experienced something like this in a long time.

I hope apple takes some action on this.

I have the same issue. Apple support just told me to use the phone less or use low power mode.

The senior advisor told me to delete some apps...

next step will be to collect data and such.

I have an eSIM and wonder if that’s the issue? Either way it definitely looks like a software bug rather than hardware.

I hope this gets fixed soon because i can’t make it through the day without charging and I am not even doing anything crazy.

My iPhone 12 battery consistently drains 1% every 2 hours while idle. So if I sleep for 8 hours my battery will be down by 4%.

However if I fully charge it to 100% before leaving it alone it’ll usually still be at 100% about 8hrs later. But if I leave it at 99% or less then it loses the 1% every 2 hours. So in addition to the fast battery drain it seems the displayed remaining percent isn’t always accurate. Seems like it might display 100% when it’s actually anywhere between 100 and 95-96%.

None of my other battery powered devices lose charge this quickly. However my last phone was the iPhone 7 Plus and that thing has always had terrible idle battery drain that I recall being about the same as this iPhone 12 even when it was new. So from my experience Apple just has terrible phone batteries. I was hoping the new phone would do better but sadly it isn’t. Even my 6 year old iPad Air 2 only loses maybe 1% after 24 hrs of idle time.

Luckily I don’t heavily use my phone so the consistent drain isn’t a huge deal, but as it stands I’m honestly losing more battery to idle drain than what I’m losing to actually using the device.

Your phone is constantly pinging cell towers all night to check for incoming calls and SMS messages, so battery use while idle is expected.

Further, have you checked Settings -> Battery to make sure no apps are unexpectedly using a lot of power?

My battery drain was about 30% during the night (approx 7hours).

2 days ago, I reset network settings and battery drain is about 13-14%... so a little bit better but I am still not fully satisfied

I have only physical SIM, 4 bars of LTE network signal, connected to WIFI

My second iPhone 7 (85% battery health, the same apps installed) has about 5% battery drop during the same period.

xhavrosh wrote:

I have only physical SIM, 4 bars of LTE network signal, connected to WIFI

If the phone is not plugged in then Wi-Fi turns off when the phone locks. So unless you keep the screen on it will not be connected to Wi-Fi.