Apple devices and a constant for battery life

Jason Snell offers an interesting analysis on the daily battery expectancy for iOS devices.

Over the years I’ve said numerous times that when it comes to battery life on iOS devices, Apple appears to have a target battery life in mind and builds its hardware—a balance of power-saving software, hardware efficiency, and battery capacity—to hit that number.

In other words, Apple thinks we need, say, a minimum of 10 hours of daily battery life and as they design each device, they make sure the battery is big enough to support that goal, but no bigger than that.

The one outlier to this model is the iPhone 6 Plus. Why? Because they weren’t driven by the need to make the phone as small as humanly possible. They had the luxury of design space, of battery headroom.



  • djr12

    Survey after survey shows that what people want most out of their devices is improved battery life. It’s puzzling that Apple continues to prioritize thinness over that issue. Nobody would have batted an eye if the iPhone had kept the same thickness over the years, and there would have been applause in the streets if the battery improved by 20% or whatever. My speculation is that it comes down to Ive’s minimalist obsession.

    By the way, as the owner of an iPhone 6 Plus for a couple of months now, I am baffled at people who report they go two days without a charge. Mine needs to be charged at least every night. It’s better, but it’s not the game-changing, iPad-like battery life reports led me to expect.

    • I still go a couple days between charges on my iPhone 5. It really depends on how much you use it.

      The iPhone is the least important part of the Mac-iPhone-iPad trio to me, but I’d hate to go back to a normal phone after using this combination. It was really the iCloud syncing that made me keep it, but Continuity has made it an even better experience.

      As for size, I don’t think it matters much from generation to generation. But compare an iPhone 3GS to an iPhone 5, and you definitely have the sense that thinner and lighter has improved the phone.

      • exactly — you cant get to a “Minority Report” state of tech by not constantly pushing the envelope. if apple said “Eh, good enough!” they wouldnt be forced to solve the difficult real engineering problems when building a real-world thin phone/tablet.

    • Keith

      Hey djr12, Take a quick look at Settings>General>Usage>Battery Usage You might find a power sucking app culprit

      • SDR97

        Keith, thanks for the pointer. I do check that info from time to time, but it basically reflects my usage — Safari, Tweetbot, that sort of thing. It would be nice if Apple provided not just the last 24 hours but the usage percentages since the last full charge, which would be more relevant troubleshooting info.

        I guess maybe I just have a different definition of what constitutes “moderate” usage than other people do. I’d say having the screen active for a couple of hours total during the day counts as moderate. But if I do that, my battery will be ~20% by bedtime.

        The one thing I’ve found that has seemed to make a bit of difference is turning off the “Share My Location” feature in Privacy > Location Services.

    • There’s already a solution if you want more battery life and don’t mind a thicker iPhone: a battery case. I got my first battery case this Christmas for my 5s (it was a filler on my gift list), and I’ve used it on a couple of outings. Still feels lighter than my old iPhone 4s and has a similar feel to my old 3G. I’d use it all the time if I found it necessary.

    • RahoulB

      Odd – I had spotify running for about 6 hours yesterday, connected to a speaker over bluetooth, with the screen on (plus the usual background stuff like facebook and so on running) – so not “light usage” – and when i went to bed it was still at 55%

      Do you travel much? i’ve read that switching cell towers uses a fair amount of battery (although that information may be out of date).

      • djr12

        RahoulB, that’s the kind of report that has me so envious, and wondering if there are different battery models or something and I got stuck with a dud. I don’t travel much at all. Most days, I work from home. I do have poor cell reception in the house, but I have the phone set to use TMobile WiFI so I don’t think it should be searching for signal all the time (and “low signal” doesn’t show up as a leading battery user in the section that Keith recommended).

        My best guess (admittedly a pretty feeble one) is that it may have to do with the sheer number of apps I have loaded on my phone, probably over a couple hundred, no one of which is drawing enough power to rate on the list in Usage, but perhaps together they are all quietly doing background stuff that is churning the phone. I keep putting off the experiment of starting from scratch without restoring and slowly adding only the essential apps…. but then, part of the reason I got a Plus with the largest possible drive is that I don’t want to have to worry about all this stuff.

        • RahoulB

          Hmm – but part of the difference between iOS and Android is that iOS apps just aren’t allowed to sit there using battery life … even if “background app refresh” is switched on (I do have it turned off for most apps), iOS is supposed to bunch together all the requests from background apps so you get little “bursts” of activity in-between lots of idle time.

          My first guess (and it is a guess) is that you’ve got a dud battery.

          • djr12

            Thanks RahoulB. I was feeling like this didn’t merit a call to AppleCare but maybe I should do it. Perhaps they have more sophisticated diagnostics they can run.

        • It’s not going to be apps you’re not running. They have no chance to draw battery power.

          From what you describe, my guess is it’s the low cell signal and it’s happening at a level below the battery monitor. It’d be interesting to try to see if that’s when the majority of your power gets drained.

          • djr12

            Steven, that does sound incredibly naive of me, doesn’t it? The only reason I even bring it up is that I’m not sure I entirely trust that an app such as Mynd, for instance, which wants to let me know when I need to leave for my next appointment, isn’t constantly cycling in the background. “Can I check now? No? Okay.” Which I suppose sounds equally absurd, now that I articulate it.

            I’d think that the cell signal search would be obviated by the enabling of WiFi calling, but perhaps iOS isn’t smart enough on that front. I know that “low signal” has turned up in the battery usage before. But not often.

          • Wi-Fi isn’t really a replacement for cell service, as your phone needs to be ready to receive calls that aren’t going to be coming over Wi-Fi. It’s not really a question of smartness but of what it needs.

            Another thing to check might be location services. With that on, I think your phone becomes more active in Wi-Fi and cell phone tower scanning to determine its location.

            The real point here is that I don’t think the battery drain rate you describe here is normal, and you can probably get something done about it. A Genius can probably help. 🙂

            Edit: And don’t worry about sound naive. This should all be simpler. It’s unfortunate that there are still enough trade-offs involved that it isn’t. 🙂

          • djr12

            Steven, I think TMobile’s WiFI Calling feature is a little different than you’re imagining, but the point is taken and the help is appreciated — I’ll talk to a Genius about this.

          • Right. It really depends on if there’s a signal to the phone that tells it that it’s okay to drop the cell radio entirely. I’m not sure if there is. Might still need it for SMS, for instance, or expecting a call that should but isn’t handled by WiFi calling.

            …that’d be something cool to ask the Genius while you’re there!

  • pchmiel

    I did some battery testing on my own (iPhone 5) and results seem to go along Jason’s reasoning. Good news is that iOS gets more power effective with each iteration.

    Results are described here: http://neverassume.info/in-english/2015/1/11/battery-life-test-iphone-5-and-ios-8