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iPad Test Notes: Battery Life

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The iPad has everyone thinking about the future of computing, but one of its greatest achievements is what it lets you forget about: battery. We pushed the iPad as hard as we could and got nearly 6 hours of use.

Early reports had the iPad's battery lasting even longer than Apple's 10 hour estimate—up to 11 and 12 hours of continuous video playback in some cases. In our test, during which we alternated between streaming video and playing graphic-intensive games, with Wi-Fi on, brightness at its highest, and the speaker at its loudest setting the entire time, the iPad's battery lasted 5 hours, 54 minutes.


By any measure, these are fantastic times, and they're essential to the success of this new type of device. If the iPad is supposed to replace your books and magazines, you should be able to throw it in your bag and read all day without worrying about a charge. For the iPad, that's a piece of cake. The fact that you can watch four or five feature length films back to back is just a bonus.

In terms of what you'll use it for, the iPad is closer to a laptop than a cell phone. But in terms of when you'll think about plugging it in, it's just the opposite, and that's a beautiful thing.


Here's how our test went:

100% - 0h 0m

0h 45m Gaming (Red Alert)
0h 45m Video (Vimeo)

85% - 1h 30m

0h 45m Video (Netflix)
0h 15m Gaming (Aurora Feint)

61% - 2h 30m

1h 00m Video (Netflix)

44% - 3h 30m

1h 00m Gaming (Plants vs. Zombies HD)

26% - 4h 30m

0h 30m Streaming (Netflix)
0h 30m Gaming (Zen Bound)

9% - 5h 30m

0h 24m Gaming (Plants vs. Zombies)

0% - 5h 54m

It's important to note that our test doesn't in any way invalidate reports of 10 hours of battery life for continuous video playback. With regular usage—watching some video here, surfing the web a little bit there—you can certainly expect to get double digit hours of battery life. We tried to run the iPad's battery down as fast as possible, and perhaps short of continuously spinning every spinnable element in the crazy Elements app, our tests show that you can expect to get at least 6 hours of juice no matter what you're doing. And it's likely that you'll get much more.


As we saw in the FCC pictures, the battery is what takes up most of the space inside the iPad (and what makes it a little bit heavier than you might expect.)


Here's what iFixIt had to say about the iPad's bulging batteries:

The 3.75V, 24.8 watt-hour (6.5 Amp hour [!]) battery provides the juice for an advertised 10 hours of use. In contrast, the iPhone 3GS has a 4.51 watt-hour battery and the MacBook Air has a 40 watt-hour battery.

The battery seems to integrate two separate 3.75V lithium polymer cells wired in parallel for such ample battery life.


Charging those batteries takes some time, and we've found that the 10W power adapter takes care of the job quite a bit faster than charging via USB from a laptop, as you'd expect. There have been some reports of the iPad failing to charge when plugged in via USB, which we've noticed here and there ourselves, too. MacWorld offers a good overview of what's going on, mainly that some older/lower-power USB ports just don't have the juice to power the iPad. Suffice it to say that the 10W USB charger is your best bet for recharging in a hurry.


Whether or not the world at large is ready for Apple's "third category" of device remains to be seen. But having a battery that can make it through the day is essential for that type of larger adoption, and when it comes to the iPad's battery life, well, you don't really have to worry about it.

Thanks to David Chaid for the grueling task of playing Plants vs. Zombies and streaming Netflix for 6 continuous hours


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