iPhone 12 battery draining fast

Yes I have the dual physical for HK. Last night I paired it with my series 6 watch and I was expecting a major drain since Bluetooth will be active all the time. This morning my phone's battery only lost 7%. Not what I expected but acceptable.

Lestat09 wrote:

Yes I have the dual physical for HK. Last night I paired it with my series 6 watch and I was expecting a major drain since Bluetooth will be active all the time. This morning my phone's battery only lost 7%. Not what I expected but acceptable.

Bluetooth uses essentially no measurable energy, so I’m not surprised.

Same thing is happening to me!! I had the XR and just switched to the 12 and I have to charge now my phone 2-3 times a day. I work sometimes with the gps but not that much, with the XR my battery life was way better and I didn’t have to charge it that many times. Don’t know what to do

Hey it seems things get mixed in this thread. Would it makes sense to start a new thread specifically pointing to our problem with the 12 battery drain issue when using two lines? I’m with you, there is most likely a problem with the DSDS module/firmware.

To all those Level 10 warriors and apple defenders:

I am at work now in 5G with 5G auto and just lost 5% in 20 minutes doing nothing but light web browsing. If I turn off 5G then it makes no difference. Even removed some app that supposedly drained the battery.

So don’t tell me this is normal because it is not. And no charging is not the permanent solution. You guys need a reminder what mobile in mobile phone means.

So I will call Apple tonight to collect some logs and get an engineer analyze this.

Are you using dual sim cards or just one ?

If you are using dual sim cards, you may try to turn off one of the two lines for a day, and see if the battery drain situation improves.

Some of us tried it out and found this method to be workable as temporary relief.

It looks like there are actually two problems, one has to do with dual sim and the other only appears while using one sim. I'm using one sim and after I replaced my iPhone 12 the drain was "only" 12% last night (down from 30%). It's still way too much. I will continue to activate airplane mode, which leads to 3-4% drain overnight. I'm not sure if Apple did some behind the scenes fixing or if it's actually an hardware issue.

Agree. Disabling the second SIM definitely makes things better, but the discharge curve is still not what I'm expecting. Last night I've killed all my widgets, Safari tabs and closed all 'open' apps (swiping them up) and then my fully charged 12Pro (single SIM) stayed on 100% for over 4 (!) hours, then slowly started to discharge at about 1% per hour. Last night I then enabled the second SIM but assured that all Apps and Safari tabs are closed and the discharge rate increased, but was still more or less 'acceptable'.

So I'm going to focus my own investigation on the widgets, open apps and open tabs. Potentially one of these prevents the handset from entering idle-mode. So indeed, it seems there are multiple issues.

The thing with Apple devices in general is, that they keep 100% battery for a really long time. The battery percentage isn't linear. I observed this behavior on many Apple devices and compared it to e.g. Android devices, which drop to 99% after a few minutes. Long story short: It's not a valid test if you charge your phone to 100% before you go to bed.

I think the widgets might not be related to this issue because the discharge curve of my iPhone 12 is back to normal while I didn't kill any widgets.

Odiebla wrote:

Agree. Disabling the second SIM definitely makes things better, but the discharge curve is still not what I'm expecting. Last night I've killed all my widgets, Safari tabs and closed all 'open' apps (swiping them up) and then my fully charged 12Pro (single SIM) stayed on 100% for over 4 (!) hours, then slowly started to discharge at about 1% per hour. Last night I then enabled the second SIM but assured that all Apps and Safari tabs are closed and the discharge rate increased, but was still more or less 'acceptable'.

So I'm going to focus my own investigation on the widgets, open apps and open tabs. Potentially one of these prevents the handset from entering idle-mode. So indeed, it seems there are multiple issues.

You’re wrong. The tower must know where a phone is. Every event (call, SMS or data) for a cellular device on the network is not sent to every tower in the world, it is sent to the towers nearest the device or phone. In order to do this the network must know where the phone is. The way the network knows is because the phone periodically sends a message to the towers near it saying “I’m here”. You don’t have to call that message a “ping” if you don’t want to, but whatever you call it, that’s the way it works.

Odiebla wrote:

Last night I've killed all my widgets, Safari tabs and closed all 'open' apps (swiping them up)

Swiping up on apps does not prevent them from running if they receive a notification. iOS just restarts them (but doesn’t show them in the quick launch screen until you open them). For example, unless all of your mail accounts are set to “manual” and not Fetch or Push all incoming mail will launch the mail app, even if you have “killed” it. The same is true for the messages app, visual voicemail, and most other built in apps such as weather, stocks, Calendar and news.

Respectfully, you're wrong here. our phone triggers an MME Update Location Request or ULR towards the HSS and updates the location. As long as the phone remains in the affiliates tracking area of that eNodeB basestation there is no need to keep updating the location. At any given time the MME needs the UE/handset it will page the TMSI of the handset in that particular tracking area and the UE will respond asking for radio resources.

So yes the network has a rough idea where the handset is but there is no meanwhile and regular 'pinging' or call it whatever you want.

Not fully aware how iOS internally handles this, but at least this is what I did last night (remove widgets and swipe all apps up and close all safari tabs) and this had a significant positive effect on the battery. On the iPhone11Pro and 8 that I'm testing with this is (as expected) not required.

I have the same issue. I replaced my iphone 11 with the 12pro last week. Noticed draining quickly. Today: Fully charged overnight. Started using at 8am. Light emails. phone in pocket til 11 am. 40% power! I will try the hard reset after catching up on some business and report back.