Worst battery life ever?

Discussion in 'iOS 12' started by travelsheep, Jun 9, 2019.

  1. travelsheep, Jun 9, 2019
    Last edited: Jun 9, 2019

    travelsheep macrumors 6502


    May 30, 2013
    Last month I got a new battery for my iPhone 6S (from my local Apple Store). I also updated from iOS 10 to to iOS 12.3.1

    I really struggle with battery. I start to use my iPhone at around 8 o'clock, read my emails. Bluetooth turned off. During the day I do some light messaging and social media. I also use Safari to read the news.

    Usually at around 15 o'clock my battery is down to 10-15 %, and dies at around 17 o'clock.

    Battery health is 100 %.

    All optimisations on iOS done, as good as I could google for tips and tricks.

    WHAT IS GOING ON? Do you have the same problem? Recommendations?


    Details for from 100% to 10%:

    Start 8 am
    Stop 15 pm

    Screen on 4h 24m
    Screen brightness 25 %

    WeChat 14 %
    Messenger 13 %
    Facebook 13 %
    Safari 11 %
    Youtube 8 %
    Chrome 6 %
    Mail 4 %
  2. cynics macrumors G4

    Jan 8, 2012
    Some of the newer tools and technologies iOS gives to developers isn't optimized for your phone.

    Example would be HEVC with x86 processors. Older CPU's don't have the hardware built in to natively decode HEVC video. So an older CPU is not only slower and less power efficient in general but it also has to work MUCH harder to do the same amount of work a modern CPU can do with little effort.

    Same applies to your (and my) iPhone CPU/GPU. For example an app using the ARKit framework on our iPhones 6S will consume more energy than an iPhone XS doing exactly the same thing. So the XS will do it faster and use less energy the whole time.

    Try to think back to WeChat, Messages, and Facebook when you first got your iPhone 6S. Consider the features that were available now that weren't available then. Using any of them is going to consume more energy then not using them at all. But even if you forego those features completely there is still features and functions the app does that now that it didn't do then that you can't avoid using because its just baked in.

    Many of those battery saving techniques are just a bunch of bunk based on knowledge from older technologies or just assumptions. Depending on your precise usage turning some things off can in an attempt to conserve battery can actually hurt battery performance. For example if background refresh is operating in the background effectively for you because you have a reliable routine then turning a specific app off can actually hurt battery performance.

    My 6S is similar to yours and I also have a brand new battery (verified its mAh capacity). In iOS 9 I got 10+ hours of USAGE, now its 5 at best. It is to be expected though, my iMac is the same way. Back in 2014 I would encode a video using h264 in a hour or so, now it takes 4 for h265 with the same video quality. I could also look at that as using 4x the amount of energy.

    TLDR - Newer features and functions are causing your phone to show its age.
  3. jrdatrackstar1223 macrumors regular


    Oct 31, 2017
    Brownsburg, IN

    One of the most straight forward and precise answers ever on here. Thanks for that tip, explains why my SE battery has gone down the toilet. Are you also saying we should leave app refresh on all the time because I tend to limit it to WiFi only. I think I have definitely noticed worse battery when having background app refresh on, however?
  4. cynics macrumors G4

    Jan 8, 2012
    Turning the API off completely will mostly be beneficial however it can hurt battery life based on specific usage. Generally battery life is negligible with it on. However if the mission was to just keep the phone on and not use it (example you don't have a charge but expecting a phone call) turning it off can be beneficial which is why low battery mode turns it off.

    The background app refresh aka background fetch api which is not to confused with other background api's like Music, VOIP, GPS, etc is highly policed by iOS.

    The main rules that apply to it are but not limited too, 1. Network conditions must be optimal. 2. Battery conditions must be optimal. 3. There is a 30 time limit until app termination. 4. Time and data is used by iOS to determine the frequency an app will be given the opportunity to fetch data.

    Number 1 is a benefit because strong network conditions use less battery than weak network conditions performing the same task. This is because the radios power consumption are based on how hard they need to work.

    Number 2 low battery or low power mode will disable it.

    Number 3 Your app has 30 seconds to send a signal that its done updating, if its not done or just doesn't send a signal that its done (call completion handler) the app will be terminated. This will prevent future background fetch until you reopen it.

    Number 4 The frequency a specific app will be given the opportunity to fetch data is based on previous events. iOS determines power usage based on time and data previously used. The more power used the less it will be allowed to fetch until there isn't an opportune situation for it to ever fetch new data in the background.

    Number 3 and 4 is what can make background fetch negligible with battery performance however I'm not denying its there and depending on usage can probably be noticeable.

    Apps that you use a lot but instinctively manually refresh you might as well turn off. If there is any battery savings to be had it will be there.
  5. Isamilis macrumors 6502a

    Apr 3, 2012
    I think the new battery might be the issue. Did you check the battery cycle?
    I also replaced the battery on my 6s last Jan. I am using 12.1.4. Starting 100% at 6am and down to around 30% at 7pm. However, I keep using WiFi almost all the time.

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4 June 9, 2019