iPhone SE Huge battery drain on SE on 12.1.2, can I leave it in low power mode all the time?

Discussion in 'iPhone' started by trfc54, Jan 12, 2019.

  1. trfc54 macrumors newbie

    Jan 12, 2019
    Picked up a used SE in quite good condition, battery health at 96%, factory restarted it with nothing on it.

    Updated to IOS 12.1.2 when it booted up, during the update the phone got really hot and when from like 76% to 62%, which may be expected. I was updating from 10.3.something.

    After the update the thing runs buttery smooth, apps open nearly instantly but the battery is draining very quickly even while just opening whatsapp or simple scrolling through the settings menu.

    I put the phone in low power mode and after doing that, I'm not noticing any performance dips and the battery is actually staying constant for significantly longer periods of time.

    Is there any downside to leaving the thing in low power mode until apple fixes its ios12 battery issues? Assuming they aren't intentional with the aim of having me buy their new, overpriced stuff...
  2. se95dah macrumors member


    Dec 30, 2014
    There’s not much of a downside, but I think your used iPhone SE might not have been in as good a condition as you think. My wife’s SE has great battery life on iOS 12. I don’t think there are issues with the OS - maybe get your phone checked out?
  3. trfc54 thread starter macrumors newbie

    Jan 12, 2019
    Besides battery health I'm not sure what other metric to use to check, to my knowledge it wasn't refurbished, but just used.

    On low power mode I was browsing, messaging, using it for like 30 minutes and it dropped only 1%.
  4. now i see it macrumors 68030

    Jan 2, 2002
    Low Power mode is good for the phone but slows it down a bit. It definitely doesn't hurt anything. It throttles the CPU speed down significantly along with other power saving schemes. It will allow the phone to run cooler, longer, but a little slower. Also Mail won't fetch automatically. Low power mode is good to use any time you aren't concerned with ultimate horsepower and want the battery to last as long as possible. Turning it on when the battery is at 100% charge is totally fine if you want to eek the most time out if the battery
  5. Significant1 macrumors 6502a

    Dec 20, 2014
    Have you checked what the battery statistics says about which apps are consuming most power.
  6. trfc54 thread starter macrumors newbie

    Jan 12, 2019
    Yes, iMessages and viber. But this is literally just opening a message and replying, takes maybe 5 seconds.
  7. Significant1 macrumors 6502a

    Dec 20, 2014
    Ok, you need start with them. It might be a hardware problem (maybe in the radio part), but you need to try some things to isolate it.
    - does deactivate imessage and uninstall Viber fix the battery drainage
    - does activate plane mode stop the drainage
    - does turning off WiFi (in phone settings not just control center) stop the drainage
    - does turning off LTE stop the drainage

    Could be that restoring to factory settings or reupdate ios (don't know if that is possible) or even doing a DFU (https://www.imore.com/how-to-iphone-ipad-dfu-mode) might help.
  8. 1rottenapple macrumors 68000

    Apr 21, 2004
    I wish there was a way to let low power mode on most of the time and increase screen shut off to time 1-2 min instead of 30 seconds
  9. trfc54 thread starter macrumors newbie

    Jan 12, 2019
    I mean, the battery is draining even just with scrolling around the settings menu. I turned off wifi, data, bluetooth, location services, siri, background app refresh, doesn't seem to have any significant improvement...

    There have been some other threads of people complaining about ios 12 on the 6s and the 7 (even the X), but I wasn't really expecting it to go down % values right before my eyes with minimal usage.
  10. BugeyeSTI macrumors 68020


    Aug 19, 2017
    I would do a restore and setup as new using iTunes and see if that straightens it out. If not, the battery might need replacement. If you have an iMac you can use coconut battery to see better information on your battery’s health. iOS native battery app is still not a good indicator as it’s not very accurate and is basically still needs improvement.
  11. iOZZY macrumors member

    Mar 17, 2013
    Stamford, England
    My original SE exhibited the same after upgrading to iOS 12 and eventually the phone would die at 10% left. The phone was only 8 months old. Apple replaced it no problem and the replacement phone is fine.
  12. trfc54 thread starter macrumors newbie

    Jan 12, 2019
    You mean just paying for the $50 battery replacement, or getting the whole thing replaced under warranty?

    Since I got the phone used, I checked the serial number and the warranty has already expired.
  13. kazmac macrumors 604


    Mar 24, 2010
    On the silver scream
    I keep my phone (formerly 7+ and now 8+) in low power mode all the time. I think that extended my battery life until iOS12.

    I also turn off screen time.
  14. FeliApple macrumors 65816


    Apr 8, 2015
    iOS 12's impact on battery life. There's nothing you can do. You shouldn't have updated, in my opinion.
  15. Significant1 macrumors 6502a

    Dec 20, 2014
    I don't have problem on 6s (same hardware), it is smooth as never before, a lot better than 11. But IOS 12 main focus was also stability and optimization (especially on older hardware) over new features. It doesn't more drain battery faster than 11, though getting an Apple watch and acting as server for it, does impact its battery. My battery health is 89%.

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