CELLULAR MODEM CAUSES BATTERY DRAIN / iPhone 12 Battery

That is an interesting and important observation. But for me, the only time I really had a drain of only a couple percent over night was when I took out the SIM card. Airplane mode helps but doesn't really do much either. I don't care wether its draining 5 percent or 15 or 30 precent. This new device is not supposed to drain so much over an 8 hours period of standby. Period.

I have 3 out of 4 cellular bars pretty much all day and get about 80Mbit's down on LTE in the house. So there is no telling me that poor reception is causing the drain in my device. In your case perhaps having only 1 or 2 bars of signal could be contributing to the drain.

However, I am 99% certain, and mostly have been, that all this is an iOS bug or modem bug for that matter where some sort of process is not being put into standby properly but keeps running constantly. The battery drain curve shows it clearly. There is constant steady drainage like as if there is a load on the CPU/battery continuously. And it's not a curve that suggests that something is coming on and draining battery and stopping again. It is some sort of low power process that uses an average of 2% battery power per hour which also runs while you are using the phone. But if you are using it, it might drain around 10% per hour (of course depending on what you actually do) and this is where most people are oblivious to the drain (especially those that charge it every night) because who cares or notices wether the phone drains 10% or 12% in an hour while using it, right!?

But losing on average 18% over night while doing nothing, is kinda a big deal.

And I hate the suggestion that I simply put my phone on a charger every evening and don't worry about it. I don't want to do that. I want to put my phone down in the evening and wake up to close to the percentage that I had when I put it down. I don't want to think about wether I need to plug my phone in before I go to sleep. I just want to glance at the battery and know that when it shows 70% and I was able to go through the entire day, I can go through the entire next day without worrying to run out. (I should mention at this point that I don't use my phone all that much.)

I don't want to do the math in the evening that if I have 70% in the evening, calculating and accounting for at least 20% loss over night, that leaves me with 50% the next morning and contemplating weather that gets me through the day and wether to plug it in now.

My 2018 12,9 iPad Pro has magnificent battery life and it is running 14.3 too (iPad OS, but still) and I simply don't have to worry about it. That's the Apple user experience that people are paying for and what they should want and deserve. And finding justification and coming up with excuses as to why this 1300€ device just can't hold a charge is ridiculous. It makes me so mad, I can't even...

I am a passionate apple user since many years and I am still, but this just makes me so angry.

Are they even testing the devices and updates they release? And this iOS beta testing seems like an utter joke. Everyone can download and become a tester and still people complain about buggy software even though they are running a beta.

And there is minor and major updates being pushed out, which add fancy features that get hyped and praised (Fitness+, ProRaw, AirPods Max Support...) and they are completely forgetting about one thing. Bug fixes that actually solve problems in the software that millions of people use every single day.

Maybe the bug is still there to completely shred older devices and force people to charge so frequently which further degrades the battery, so people would finally give in and upgrade from their trusty 6S and get a new phone and to discover that even the new phone has the same problem. Big LOL. Ask me how I know

And basically all I am trying to do (and a lot of people here asking and contributing to the Battery drain topic) is trying to isolate what is causing the issue. And I cannot believe that so many people have poor cell connection that makes their iPhones consume so much power.

I am familiar with the battery drain when I am in a really low reception area (there is a 2km stretch when I am on the train where there is no signal). Experience made me enable airplane mode every time I entered that zone but sometimes when I forgot, I went in with let's say 50% and 3 minutes later had only 40% left, only because the reception gets less and less until its completely gone and the phone tries to stay connected until I just can't anymore, I know that is when the excessive drain happens.

First of all, thanks for your reply.

Yes I am aware of that. I am home and connected to Wi-Fi virtually all the time (like pretty much everybody these days). But only having the phone sitting on a desk with the SIM card installed, Cellular Data on/off doesn't matter, with a signal strength of 4 bars and airplane mode on/off doesn't matter much either, the battery drains significantly without me touching the thing. Dammit, I sound like a broken record.

But as soon as I pull the SIM and enable airplane mode (which in my head pauses most processes the modem does), after a couple hours and then checking, I lost nothing or maybe 1%.

I do get that connecting to a cell tower, searching for signal and stuff like that does consume power but I think it shouldn't consume as much as it does.

Exactly. That's why I thought it would be a good idea to ask people where they are located and on what carrier they are. As far as I know, it is mainly 12 users that suffer from the bizarre drain. The overnight drain of 20% or more over the course of 8 hours is present durning the day as well, but stretched over the entire day and mixed in with the actual usage, so a lot of people, especially everybody who charges their devices overnight might not even be aware of this because during the day, those 20 percent go relatively unnoticed and people only think 'Hmmm. This battery life is really not what I expected from a new device' and may be complaining about overall poor battery life and hack around about the small fact that the 12's battery has a 400? mAh smaller battery compared to the 11's. Whereas it is actually a bug (or something else) that kills 20%+ just eating away battery in the background regardless, no matter if you are using your phone or not, that doesn't show up in the battery usage view.

For everyone reading Lawrence Finch's, you also have to make sure that Significant Locations and System Customization are on in order for optimized battery charging to work. It also will take a couple days or more to fully set up, so the phone knows when you get up etc.

I find it baffling that Apple does not fully explain it right there in the menu. The switch in the battery menu might be on, people think they have the feature enabled whereas they are very likely have gone into the location services at some point and disabled most things there because they wanted to save battery life. If one doesn't look at the graph, one has no idea that the optimized charging does in fact not work at all with does do toggles disabled. Why is the optimized battery charging toggle not greyed out and telling you that those location service options have to be enabled in order for it work.

Most people spend far less time thinking or testing these things compared to us 'nerds' ;)

Normal people look at a video 'how to save battery on an iPhone' where it says, 'toggle on optimized battery charging' and in the next step to disable location services entirely.