How long does it take to charge "New iPad" (iPad 3)

Discussion in 'iPad' started by PracticalMac, Apr 9, 2012.

  1. macrumors 68020

    Joined:
    Jan 22, 2009
    #1
    Have not charged from fully drained state, but did 48% in just over 3.5 hours, suggest about 8 hours to charge from 0% (stand by mode almost entire time).

    Actually boggle my mind, all that battery power. 25 W·h(!).

    ...Considering the charger is 2.1Amp, for 25W-h, suggests over 10 hours to charge from 0%. (musing)
     
  2. macrumors 68000

    Joined:
    Jan 26, 2008
    #2
    Mine takes 6 hours.
     
  3. macrumors 65816

    Joined:
    Apr 19, 2011
    Location:
    Austin TX
    #3
    Mine takes about 6 hrs too. This is from around 10% to 100%.
     
  4. macrumors 68000

    richpjr

    Joined:
    May 9, 2006
    #4
    Another one here with around 6 hours - just plug it in before bed and it's ready in the morning.
     
  5. macrumors regular

    Joined:
    Mar 31, 2012
    Location:
    Athens, Hellas!
    #5
    6 hours and 15 minutes
     
  6. macrumors G5

    Macman45

    Joined:
    Jul 29, 2011
    Location:
    Somewhere Back In The Long Ago
    #6
    Yes, between 6 and 7 hours seems to be the norm.
     
  7. macrumors 6502a

    Joined:
    Sep 25, 2003
    #7
    The battery is 42.5 watt-hours.

    The charger is rated for 2.1A, 5.1V. 2.1*5.1=10.71. So, in THEORY, you get 10.71 watts but with the voltage loss on that flimsy wire, you'll never see more than the 10watts total power the charger is marketed as (4.76 volts at 2.1A, and technically it's not a charger, it's a power supply, the actual charger is in the iPad, but still...). So we'll run with Apple's 10 watt figure, also because it's a nice number.

    That means that theoretically, assuming 100% efficient charging, the battery COULD charge in 4 hours, 15 minutes (4.25 hours). Nothing is 100% efficient, and the last 10% or so of a lithium ion battery charge must be done very slowly. Still, with the device off, you should get at least mostly charged in 5-6 hours in paper. If you're using it at all, this goes down.

    Now, if you use a smartphone charger... 1A at 5V is 5 watts. Theoretical minimum charge time would be 8 hours, 30 minutes. Again, assuming non-existant 100% efficiency. Also again, the device is OFF in this assumption and any use is even more likely to prevent the iPad from charging at all, and making it more likely to drain (just more slowly) while connected.

    Finally, with a computer USB port or standard phone charger... 0.5A at 5V is 2.5 watts. Theoretical minimum charge time becomes 17 hours (100% efficient charging again, not realistic). In reality, the chances of this charging the device are slim, but at least the battery will drain a bit slower...
     
  8. macrumors 68040

    h1r0ll3r

    Joined:
    Dec 28, 2009
    Location:
    Maryland
    #8
    7-ish from 0 - 100%
    About 6 hours or so for regular charging. I seem to have an issue with the battery percentages displaying inaccurate info like some others have noted. I charged mine overnight and it went from 45% to 58%? How random is that. Anyhoo, after hard reset, it went back to 100% but then stayed there for about 6-7 hours. After another hard reset, it dropped to 30%. Had to recalibrate the battery a couple times but I think it's working properly now.
     
  9. macrumors 68040

    D.T.

    Joined:
    Sep 15, 2011
    Location:
    Vilano Beach, FL
    #9
    Yeah, I’m seeing about 6 hours or so too.

    The longer charge period hasn’t been an issue for me. I have a charger at my desk, so I just connect it when I’m done for the day or occasionally while I’m using it (for video for example) - also have another charger upstairs, so if I’m using it at night, when I’m done I just connect it right at my nightstand.

    So in the morning it’s at 100%, and given my use, I don’t even have to charge it but every 2-3 days anyway. :)
     
  10. macrumors regular

    Joined:
    Mar 19, 2012
    #10
    6.5 hrs for mine. I charge up every night. Usually end the day at about 20% remaining.
     
  11. macrumors 68000

    spiderman0616

    Joined:
    Aug 1, 2010
    #11
    I've said it before and I'll say it again:

    Who cares? Don't people mostly charge at night while they're sleeping? And if you do need to charge it during the day, charge it for a couple of hours and leave!
     
  12. thread starter macrumors 68020

    Joined:
    Jan 22, 2009
    #12
    Thanks for all that! Explains it.

    I likely over estimated total time, probably less then 7 hours on my end too.
     
  13. macrumors regular

    Joined:
    Mar 31, 2012
    Location:
    Athens, Hellas!
    #13
    We all know that it is not good to leave the iPad on the charger when it is fully charged! So this is one good thing about taking so long to charge, when you charge over night you wake up the iPad has not been left fully charged on the charge for a long time! :)
     
  14. macrumors regular

    Joined:
    Sep 14, 2009
    #14
    This is simply not true:
     
  15. macrumors regular

    Joined:
    Mar 31, 2012
    Location:
    Athens, Hellas!
    #15
    Thanks for clarifying this!
     
  16. macrumors regular

    ewo1992

    Joined:
    Mar 11, 2012
    Location:
    Southern, CA
    #16
    Mine takes.... I don't know. Plug it in when I to to sleep.... Wake up and it's fully charged.
     
  17. macrumors regular

    Joined:
    Jan 30, 2008
    Location:
    Manchester, UK
    #17
    All I know is that if I plug it in before bed and it's still not charged by morning I've had a crappy night's sleep :D
     
  18. macrumors member

    Joined:
    May 3, 2011
    #18
    Interesting to see how people's iPads take differing amounts of time to charge. Mine takes about 12 hours from 1%-100%. I have it currently charging and in 5 hours it has charged less than 50%.
     
  19. macrumors regular

    Joined:
    Mar 31, 2012
    Location:
    Athens, Hellas!
    #19
    Are you using the supplied iPad charged or an iPhone one? It is normal to have small variations due to the different losses that each charger has but 12 hours is double the time!
     
  20. macrumors 68030

    verwon

    Joined:
    Jul 26, 2011
    Location:
    Seattle
    #20
    Honestly, I've never sat down and timed mine. If it's low, I plug it in and don't worry about it. Usually, that's at night, when I'm going to sleep, anyway.
     
  21. macrumors member

    Joined:
    May 3, 2011
    #21
    I am using the supplied charger. Is there a difference in charger between the iPad2 and New iPad charger as the wife has an old machine and I use her charger sometimes.
     
  22. macrumors 68030

    MrXiro

    Joined:
    Nov 2, 2007
    Location:
    Los Angeles
    #22
    Are you plugging it into a computer or an outlet? No way should it take 12 hours from an outlet.
     
  23. macrumors member

    Joined:
    May 3, 2011
    #23
    Straight into a wall socket.
     
  24. macrumors 68030

    MrXiro

    Joined:
    Nov 2, 2007
    Location:
    Los Angeles
    #24
    I would take it to the apple store or exchange it.
     
  25. macrumors member

    Joined:
    May 3, 2011
    #25
    Shame...as the iPad is perfect apart from this.
     

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