Battery Life

With the iPad Air Apple moved to a 32.4Wh battery, a significant decrease from the 42.5Wh unit in the 3rd and 4th generation iPads. The smaller battery doesn’t come with a change to Apple’s claim of 10 hours of battery life, which implies a reduction in overall platform power. I confirmed a substantial reduction in platform power in my crude measurements earlier in the article. Although it’s possible for the iPad Air to draw substantially more power than the iPad 4, our earlier power data seems to imply that it’s unlikely given the same exact workload. Our battery life tests agree.

We'll start with our 2013 smartphone/tablet web browsing battery life test. As always all displays are calibrated to 200 nits. The workload itself is hidden from OEMs to avoid any intentional gaming, but I've described it at a high level here.

Web Browsing Battery Life (WiFi)

Our web browsing workload came in at exactly 10 hours of continuous usage - an improvement compared to the iPad 4. Battery life on LTE was good as well, consistently delivering just under 10 hours of usage. The fact that both LTE and WiFi tests deliver similar results tells me that we may be bottlenecked by some other component in the system (perhaps display?).

I've been running the same video playback test for a while now, although we're quickly approaching a point where I'll need to move to a higher bitrate 1080p test. Here I'm playing a 4Mbps H.264 High Profile 720p rip I made of the Harry Potter 8 Blu-ray. The full movie plays through and is looped until the battery dies. Once again, the displays are calibrated to 200 nits:

Video Playback Battery Life (720p, 4Mbps HP H.264)

Video playback battery life also improves slightly compared to the iPad 4. Apple’s battery life claims aren’t usually based around video playback, so exceeding their 10 hour suggestion here shouldn’t come as a shock. Apple’s video decode power has always been extremely low.

Our final cross-platform battery life test is based on Kishonti's Egypt HD test. Here we have a loop of the Egypt HD benchmark, capped to 30 fps, running on all of the devices with their screens calibrated to 200 nits.

3D Battery Life - GLBenchmark 2.5.1

Our 3D battery life rundown test shows a substantial improvement in battery life over the iPad 4. IMG’s PowerVR G6430, running a moderate workload, can do so more efficiently than any of the previous generation GPUs in Apple’s SoCs. Much like the A7’s CPU cores however, there’s a wider dynamic range of power consumption with the G6430. Running at max performance I would expect to see greater GPU power consumption. The question then becomes what’s more likely? Since the majority of iOS games don’t target the A7 (and instead shoot for lower end hardware), I would expect you to see better battery life even while gaming on the iPad Air vs the iPad 3/4.

Charge Time

The iPad Air comes with the same 12W USB charger and Lightning cable that we first saw with the iPad 4. Having to only charge a 32.5W battery means that charge times are lower compared to the iPad 3 and 4:

Charge Time in Hours

A full charge takes a little over 4 hours to complete. The adapter delivers as much as 12W to the iPad, drawing a maximum of 13.5W at the wall. I still think the sweet spot is somewhere closer to 2.5 hours but that’s another balancing game that must be played between charge time and maintaining battery health. It’s still so much better than the ~6 hours of charge time for the iPad 3 and 5.69 hours for the iPad 4.

WiFi & LTE Connectivity Usability, iOS 7 and the Impact of 64-bit Applications


View All Comments

  • jonjonjonj - Tuesday, November 5, 2013 - link

    but they are such an innovative company. look they released another iphone with a different size screen. Reply
  • nerd1 - Wednesday, October 30, 2013 - link

    Kindle HDX actually uses magnesium unibody case. Reply
  • Kamus - Wednesday, October 30, 2013 - link

    It is really only a "more limited device" just because it is a much newer plataform. Not because Apple is a super-open platform. Also, it is not plastic, but magnesium. And its also 130 dollars cheaper... It wouldnt hurt to get your facts straight before you drop those "knowledge" bombs on us.
    I would have bought one right now if the App Store had more developer support.
  • JarredWalton - Wednesday, October 30, 2013 - link

    100% RGB gamut means nothing if the display isn't factory calibrated. Actually, it means highly oversaturated colors, as most content is designed for sRGB. Reply
  • Kamus - Wednesday, October 30, 2013 - link

    Actually, 100% means it should fit the sRGB triangle perfectly. And the reason it does this, is in fact, because it IS factory calibrated. The amount of ignorance and bashing on the HDX is cringe inducing. All the info is right there on the amazon product page. Reply
  • KoolAidMan1 - Wednesday, October 30, 2013 - link

    100% color gamut and being properly calibrated are two completely different things. You have no idea what you're talking about. Reply
  • Kamus - Thursday, October 31, 2013 - link

    No... They are not "completley different things". There is grayscale calibration and gamut calibration. If they claim 100% sRGB it suggests that they are gamut calibrated. And again, the reason that i said that the HDX is factory calibrated is because it says so right there on the Amazon product page. All you did is the same thing everyone else is doing by sprouting nonsense with out even bothering in doing any research at all. Reply
  • Boissez - Wednesday, October 30, 2013 - link

    One thing is marketing material an another thing is actual reality. By Ars Technicas measurements the HDX covers about 90% of sRGB - the iPad have been at 94% or over ever since the first retina iPad. Reply
  • youmenimum - Wednesday, October 30, 2013 - link

    pixel density alone is not a quality to consider. In real comparison kindle tablets are not good at display compared to iPad. which one are you using by the way? Reply
  • Kamus - Monday, November 4, 2013 - link

    It's been settled. The kindle fire HDX 8.9 has the best display on any tablet as of today:

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