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

  • Ins0mnihack - Friday, November 1, 2013 - link

    As an owner of a 2nd gen Nexus 7 and iPad 3 (soon to be replaced by an iPad Air) I have to largely agree with this. While I wouldn't call the Nexus 7 a "POS", its an inherently cheap device with an incredibly limited selection of tablet optimised apps.

    While I vastly prefer the flexibility and freedom of Android (particurarly when it comes to app intents, and choosing default apps) it still doesn't make up for the severely lacking ecosystem for Android tablets. And while the Nexus 7 does have a nice 1200p display, the Tegra 4 chipset doesn't seem capable of driving Jellybean at a nice frame rate (or maybe it's just the inherent micro-stutters of Android - either way it stutters when scrolling and during quite a few system animations). iOS's touchscreen responsiveness and frame rate are still much better than Android.
  • ESC2000 - Sunday, November 3, 2013 - link

    Um I'm really doubting you own a nexus7 based on your comments. It has a Qualcomm snap dragon processor, not tegra 4, and it has 4.3. The processor runs it like a charm. The nexus even has a nicer screen than all the 10 inch iPads including the iPad air not to mention it ismuch more reasonably priced. something all non windows tablets lack is good multitasking. A 10" iPad like the air should be more than a gigantic iPod touch. Reply
  • Lizbeth - Sunday, November 3, 2013 - link

    I dunno. The Amazon HDX is pretty tight and isn't listed in the comparison. They are easy to hack and add full google play functionality even if it does void the warranty. Why is Amazon Fire HDX not listed in the comparison? Reply
  • Walkop - Tuesday, November 5, 2013 - link

    I like your comment.

    It makes me laugh. :D
  • akdj - Wednesday, October 30, 2013 - link

    An absolute and collective "AMEN" John2k13! Thanks for the excellent response...a breath of fresh air---and excellent response from the drivel Mr. dsumanik tries to lay down as 'issues'. Unreal.
    Anand....and the rest of the crew, thanks once again---a magnificent review as always! The depth you...and your crew go to is as extensive as it gets and IMO, easily the most 'objective' on the 'web.
    Thanks again....would be nice for the comment section to be a 'paid' or 'donation only' area---where those that have the ability or should I say---the 'privilege' to post would have to donate to your cause;)
  • pdjblum - Wednesday, October 30, 2013 - link

    lol. Your kidding right? Maybe they could make it so only people who agree to kiss anand's ass should be able to comment. Reply
  • robco - Thursday, October 31, 2013 - link

    *you're Reply
  • akdj - Monday, November 4, 2013 - link

    Not're the joker here bud Reply
  • teng029 - Wednesday, October 30, 2013 - link

    Well said. No one is forced to come to Anand's site to read his reviews. Don't like the way he reviews products? Go somewhere else. Most of us actually appreciate the fact that he does a very thorough job of reviewing products that come his way.

    As for those asking for Thunderbolt on an iPad, you seem to forget that Apple does not own Thunderbolt; Intel does. You also seem to forget that iDevices are based on processor technology owned by ARM; Intel's competition. Why would Intel allow their proprietary technology to run on a competitor's platform?
  • Djasonw - Thursday, October 31, 2013 - link

    Your thoughts and comments mirror mine. Well said. Some people are VERY dumb. Reply

Log in

Don't have an account? Sign up now