CELLULAR MODEM CAUSES BATTERY DRAIN / iPhone 12 Battery

The absolute best thing you can do to preserve the battery is to charge the phone overnight. The smart charger in the phone will stop charging when the phone reaches 100% (or 80% if Optimize Charging is on), then power the phone with the external source. Once it is charged the battery is no longer powering the phone; instead the external power source is. The longevity of the battery is primarily a function of how often it is charged. Every time it is charged it loses a little bit of its life. More specifically, it is rated to remain above 80% capacity for 500 full charge cycles (0-100%, or a combination that adds up to 100% such as 50% to 100% twice or 40% to 60% 5 times). Converting to real numbers it will lose about 1% of capacity for every 25 full charge cycles. So the best plan is to reduce how often you charge it, and one way to do that is to use mains power whenever possible rather than using battery power, then recharging it.

Letting it run on battery power overnight will shorten the useful life of the battery, regardless of whether it is draining 5% or 20%.

You need to go to Settings/Battery and see what is using the most energy. It doesn’t resolve the issue, but it does extend the life of your battery. One simple observation. If you charge overnight, and you don’t have to charge during the day to keep the phone working until you charge it again overnight it is working as expected.

And what i told, with airplane ON, there is only 4% drain on 12 mini. And on my iphone 7 in the same place, in my flat, there is maximum 7% drain in standby with airplane OFF,, but 12 mini is 20-25% drain overnight

As I have explained, when the phone is not plugged in all apps that need data (even overnight) will use cellular data, and cellular communications is one of the heaviest energy users on the phone, especially so if the signal strength is not the strongest.

As I have also said, charge the phone overnight, every night. It is better for the battery, allows automatic daily backups and leaves you with a fully charged phone when you get up in the morning.

I am not going to respond again if you refuse to charge the phone overnight.

First of all, thank you for taking the time to write all of the above, the 5% point you made actually makes complete sense now.

however, considering what you said about what the phone does on its own overnight, after the very first couple of nights that i noticed this huge drain i turned a lot of things off. I have disabled any options that i see that update stuff with cellular data, I have background app refresh off, i even turned my icloud sync and back up off cause i was very worried that this drain will eventually affect my battery’s health. In fact, like a complete idiot, because i’ve disabled the icloud back up I do a manual backup on my laptop just to be safe until i find a solution (please dont make fun of me😅).

the reason i am concerned is I never encountered any issues with my iphone 7, and I didnt even play around with any settings cause there was no need for me messing anything up. Which is also why i’m kind of stumped on what i’m supposed to do and i find it very hard to wrap my head around just accepting 20%+ battery drain per night as normal.

As i said, cellular data is disabled for some things I could find, i anyways have it turned off while at home, only wifi is on in terms of connectivity. Please do correct me if im wrong, but what happens in the long run if my battery keeps draining randomly every night but for my convenience and of course the benefits you mentioned, it keeps charging while something is draining the battery? I dont know if I’m explaining my concern correctly...

apologies for the long post and if i dont make any sense, thanks in advance for anything you have to offer!

Wow I didnt know all of this and thanks for educating me! I’ll definitely try it and hope for the best, you sound like you know a lot about what you’re talking about, lol! I still dont understand why this is a problem for me now vs my previous phone, but what you suggested sounds like the most sustainable option and I’m sure a lot of people would be able to benefit from this, hopefully those who need this advice will see it.

@user0197 thanks for your suggestion as well, I totally feel for you I think we’re in the same boat right now, but if I’m going to be honest I’m going to change my charging habit as per Lawrence’s advice, cause it sounds the sensible thing to do until we find out if there’s an actual problem with the 12 series or not. For me, taking out the sim, airplane mode and switching to 3G are all a hassle - a mild annoyance that I know I am not going to keep doing for a long time. As you said doing all this and changing the setting does indeed make our phones “dumber” and they’re supposed to make our lives easier not more difficult lol.

my battery usage looks pretty similar to yours, with switching to 3G and airplane mode (just so you know it may be an option for you if you dont want to charge overnight). But, with mild everyday use after 24 hours would still have to charge it which for me was mostly after I woke up. I’ll try Lawrence’s advice and fingers crossed with the same usage I get two 24hs!

Best of luck and thanks to you both once again.

I think, we talking about different issues. U told how to explain battery life, but i told about drain with the same configurations on iphone 7 and12 mini.

That is my today battery graph, but i will test it tonight one more time, because this was first time test last nightwith airplane ON. Now is 28% of battery.

Ok, but this help is not resolve the issue with battery drain, because drain will continue when i use my phone during the day.

Unless you have exactly the same apps on both phones, and exactly the same settings, and exactly the same data a comparison between 2 different devices is pointless.

12 mini - 3% battery drain per 5,5hrs at night after update to 14.4

20-25% drain, 6hrs, with 14.3