12W Power Adapter (20% faster charge)

Discussion in 'iPad Accessories' started by Bheleu, Oct 23, 2012.

  1. Bheleu macrumors 6502

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    Nov 16, 2010
    #1
    New on the AppleStore:
    http://store.apple.com/us/product/M...er?fnode=48&fs=m.iphoneCompatibility=iphone_5

    Comes with the iPad 4th Gen. At 12W instead of 10W, expect a 20% faster charge rate. Unknown if it takes a lightning cable to get the full 12W of power or if an iPad 3rd Gen will use the additional power.

    Currently 10W will barely keep an iPad 3 happy and in some instances continue to drop in power if running intense gaming at max brightness.
     
  2. ZipZap macrumors 601

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    Dec 14, 2007
    #2
    Its not the charger that matters is the device's charging hardware and software.
     
  3. al256 macrumors 6502a

    al256

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    Jun 7, 2001
    #3
    Oh baby! That's nice.

    Thanks for pointing this out.
     
  4. dasx macrumors 65816

    dasx

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    #4
    Correct me if I'm wrong but they don't state anywhere that charging times will be a 20% faster.
     
  5. nuckinfutz macrumors 603

    nuckinfutz

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    #5
    He's doing the math based on battery charging scaling in a linear fashion.
     
  6. TroyBoy30 macrumors 68000

    TroyBoy30

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    #6
    Never noticed any issues with charging my 3rd gen. I plug it in when I go to bed and its charged when I get up even when it was completely dead.
     
  7. GrandPhrase macrumors 6502

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    Jun 16, 2012
    #7
    I believe he stated so because 12W is a 20% increase from 10W. Not sure if the proportion of increase wattage to charging rate is linear, but I believe those were his thoughts.

    ----------

    Will the 12W adapter charge the iPad 3rd generation at a faster rate or will it only affect the iPad 4th generation?
     
  8. Yr Blues macrumors 68020

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    #9
    if so, then they should've hyped it at the keynote

    we'll see
     
  9. w00t951 macrumors 68000

    w00t951

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    #10
    Device charging is regulated entirely from the device. According to the laws of thermodynamics, increasing the rate of charge also exponentially increases heat output (and therefore lowers efficiency). I guess Apple might allow the iPad 4 to charge a bit faster, but nowhere near 20% as the OP suggested.
     
  10. gmanist1000 macrumors 68030

    gmanist1000

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    #11
    So will it still charge the iPad 3 20% faster?
     
  11. w00t951 macrumors 68000

    w00t951

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    #12
    Look up.
     
  12. GrandPhrase macrumors 6502

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    #13
    So the faster charging from the 12W only affects the 4th Gen iPad and not the 3rd Gen iPad, correct (as you stated device charging is regulated from the device)?
     
  13. w00t951 macrumors 68000

    w00t951

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    #14
    I don't know. Apple decides how fast the device charges, so I guess that's a possibility.
     
  14. dasx macrumors 65816

    dasx

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    #15
    My point exactly. A 12W charger doesn't necessarily imply that charging times will be a 20% faster. The iDevice can only handle a certain input and it's itself who manages that input.

    From my experience, the iPad charger seems to charge the iPhone a bit faster than the regular iPhone charger, so this new 12W adapter might as well decrease a little bit charging times, but we can't say it's gonna be a 20% faster cause it could even be slower (not probable scenario, lol).
     
  15. Bheleu thread starter macrumors 6502

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    Nov 16, 2010
    #16
    The outer two USB pins are power pins. The inner two USB pins are data pins. Unknown is how they handle battery management and if they utilize the data pins while charging batteries, or use these pins to identify the capabilities of the attached Apple brick. If they do use the data pins to manage current rate with the charger, and if it is part of iOS firmware, etc. the iPad 3 may still take advantage of the increased power capability of the charger. It just depends upon how Apple has designed the battery management system.

    For instance, increasing the charge rate would increase the temperature of the device itself as it charges. Apple may have it such that it reduces the rate of charge if a temp sensor gets too hot. It may also have a default for what it can charge at. I know when I use a cheap charger, or if my wife uses a charger with her screen brightness set to max she has charge issues where it will not recognize the charger - so I have no doubt that Apple has some "smarts" built into the charging system.

    The 20% increase is additional power that is available from the power brick.

    5VDC is USB Voltage so instead of 2.0A with a 10W charger; thereoretically if it pulls the maximum current it can now go up to 2.4A during its max charge cycle. When the battery gets to peak charge, typically most battery management systems go into a trickle charge (where it gives it less current).

    Power = Voltage * Current

    I was going to get one the other day, but the Apple store only had 10W chargers on the shelf. The assoicate was not aware of the new adapter, but he was interested in finding out about it.
     
  16. KeepCalmPeople macrumors 65816

    KeepCalmPeople

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    #17
    That would have implicitly acknowledged that the 10W adapter that shipped with the iPad 3 was inadequate - given that the battery size is the same in the iPad 4.:eek:
     
  17. dasx macrumors 65816

    dasx

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    #18
    Doesn't matter anymore. Apple themselves said it'll charge previous devices faster!! They didn't say it was gonna be a 20%, they didn't even say a specific %, but they stated it should be faster.

    http://9to5mac.com/2012/10/24/apple-confirms-that-12w-adapter-will-charge-ipads-quicker-than-older-10w-adapters/
     

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