iPhone 12 battery draining fast

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

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.

Why don’t you follow the best practice of charging the phone overnight? It will extend the useful life of the battery, it will assure that it is fully charged at the start of the day, and, if you turn on iCloud Backup it will create a new backup every night.

For me it looks like this. My iPhone 12 lost about 30% during the night without any information about which app / process causes this drain. What's even worse is the fact that I enabled the power saving mode which, in theory, disables all the background processes of apps. I already replaced my iPhone 12 but my new unit is losing about 20% again. My workaround right now is to enable airplane mode, which seems to be working. Obviously it's not an fix. I'm using single sim.

Well, I just read the follow up post, where he says 2-3 bars, sometimes 1. So my response stands. And 4-5% overnight, which is normal if you don’t charge overnight. While Apple hasn’t published the idle statistic for a while, it is probably the same 200 hours it always was. That works out to a standby discharge rate of 0.5%/hour. So in 8 hours it would be expected to drop 4%.

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.

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.

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.

Your curve looks terrible, though different from some others including me using dual sim. If you’re within the 14 days return period, return it. I’m in contact with Apple support but they have no clue. I suspect it’s a serious issue.

my story with 12pro:

1 SIM Card, LTE, no 5G, no esim

I declare "battery drain" = 3-5% lost in idle, no app open, display off

• bought it with 14.2, so no idea what would have been under 14.1
• copied settings from old phone -> battery drain
• waited 2 days, hoped it might have been "indexing" -> battery drain
• updated to 14.3b1 -> battery drain, but some idle periods without drain, but then drain again
• connected to finder yesterday and set it to recovery mode, fresh install of 14.2 (download on mac in finder)
• setup as fresh phone, new phone, I had to put all the credentials and wifi settings ("ME very unhappy user now!")
• update to 14.2.1
• installed some apps, but not all I use usually
• battery drain, now I have to charge

Well, just to decide to give it back and wait a couple of months buying a new one, or give 14.3b2 a try...

This is no good start for such an expensive device!!!

So first night on 14.2.1 and my battery depleted 15% overnight, no fix for me. Just for context, I received my device on day one I’ve had battery drain on standby since I’ve had it of around 12 to 25% and it varies per night. I’ve been to Apple support who advised me to do a hard reset via finder on MAC. I have done everything they advise me to do and it’s still not fixed. I really hope they can sort this because it is really affecting my experience of the device.

Same issue here... I'm using the iPhone 12 with one physical SIM (German Telekom 4G) for 4 weeks and tried everything.

When I received the phone I transferred a backup of my iPhone8 first, after some days I did a complete fresh install, and then I tried something else every day (eg. a reset of the network settings, a hard reset, a soft reset, I even reset my WiFi router some days ago).

As you can see on the screenshot it doesn't matter if I'm using the phone or not, the battery drain is more or less the same.

My iPhone 8 used about 3 or 4 percent battery overnight and the iPhone 12 about 3 or 4 percent per hour when idle...

Hopefully this is software related and Apple is aware of this and will fix it soon.

After tweaking up with my basic tips I give you before. My iPhone 12 Pro phone was in idle mode in about 9 hours under the night. I also use E-sim on the phone...

Here you can see the result:

I only lost 9% of the battery for the whole night 😊

Well, back on LTE after a successful experience with 3G in standby mode ... and battery drain back , -25% per night ! ( LTE is just eating up the battery at an inexorable speed doesn’t matter sim or e-sim)

OK, at 7 this morning I did a full DFU restore on my 12 mini and set it up as a new phone with nothing from my old backup. I have installed 10 or 12 applications from scratch, all of which ran quite happily on my SE and did not cause power drain. And I am still, 4 hours later, seeing the same rate of power drain as previously.

I'm giving up on this phone - mine is going back for a refund. I'm starting to think that those of us who are seeing this problem have modem chips which have a hardware fault; I've now tried everything I can think of to fix this through software. If Apple address this in future, I might buy another 12 mini in 6 months time, when they have fixed the bugs, but for now, this is not fit for purpose.