Apple Explains Why iPad 3 Continues to Draw Power After Reporting 100% Charge

Last week, we reported that the new iPad continues to draw power even after the iOS battery indicator reports 100% charge.

This led to speculation that there was a bug in iOS battery indicator. But, it looks like the behavior is nothing new to iOS devices. You should ideally notice a similar behavior while charging an iPhone or iPod touch.

Apple’s VP Michael Tchao has clarified to AllThingsD that this is not a bug, but it is feature of iOS to maintain optimum charging when the device is plugged in.

Here’s how it works:

Apple does in fact display the iPad (and iPhone and iPod Touch) as 100 percent charged just before a device reaches a completely charged state. At that point, it will continue charging to 100 percent, then discharge a bit and charge back up to 100 percent, repeating that process until the device is unplugged.

The discharging and charging of battery has been one of the source of the confusion. But Tchao explains that it is being done to keep your iOS device plugged in as long as you like:

“That circuitry is designed so you can keep your device plugged in as long as you would like,” Tchao said. “It’s a great feature that’s always been in iOS.”

No matter where in that cycle a battery is, Tchao said, owners of the new iPad can expect the 10 hours of battery life that Apple has promised.

The decision not to keep changing the battery status was designed so as not to distract or confuse users.

That explains why iPad 3 continues to draw power after reporting 100%.

It is strange that we haven’t noticed this before, but it is probably because the new iPad comes with a huge battery and this discharging and charging process when it is plugged in is more noticeable than previous iOS devices.

  • XinC

    How does this explain why it stops after 1 hour. If the explanation was true, we should see continuous power draw well after 1 hour.

    • Mandersoon

      That’s because it starts that cycle while it’s charging. It stops after an hour because that’s how long the cycle last. Afterwards, it adjusts so it’s not as noticable.

  • Fattrain

    It makes perfect sense…
    If you’ve ever used third party charging apps they always have about another 10-30min after they get to 100% of trickle charging e.t.c.

    This is nothing new…. I knew my iPhone 4 and 4S had both did this….. But apparently most Apple guys are just figuring this out ;-)

  • Delana

    Makes perfect sense, over charging any battery is damaging to it. Thus, to prevent damaging the product Apple builds in a protection.

  • http://no Hing kong

    my battery charged 100 percent, and then unpluged automatically

    • mato

      there is a ghost in ur house… really there is

      • Paul

        LOL!!!

      • http://no Hing kong

        I am not a house.

  • BlueDream

    maybe there is supernatural activity ….

  • Macintosh?

    what about the MacBooks? do they have this safe protection to the battery?

  • iOS5

    You fun boys are a bunch of morons. Sorry but I have to say this. Like the other OP said . If this BS explaination were true, why does it completely stop charging after showing an hour and half after showing a 100%. Same story SJ spinner about losing signal because users don’t know how to hold the iPhone correctly. Please stop drinking the coolaid. Yes I do like apple products but I can smell BS from a mile away.

    • iOS5

      Another piece to think about; charging and discharging also reduce your battery life span. If so many companies make charging mechanisms that shuts the power down as to not overcharge your device, you believe apple doesn’t have that technology?????

  • Trapp

    Dear iPH.com could You please do a test An easy one – charge Your iPad 3 until it shows full unplug it at once and count time until battery runs low. Charge it again until full PLUS 2 hours. Then discharge it exactly same way and compare timings. Thank u.

  • JC

    Then what’s the purpose of the icons displayed in the battery icon on the top right corner? it displays a charging icon even when it is at a 100% if it is still charging and then it changes to other icon with a plug in the battery when it really gets to a 100%, or at least that’s what I’ve always understood but I’ve never seen those two icons changing when I have my device plugged in… but the charging and discharging thing when the device is plugged makes sense, that way you don’t ruin your battery if you have your device plugged for a long time.

  • http://www.motorbeam.com/ fas

    the explanation is sort of not believable.

    • Trapp

      Bullsh1t suits better ^^