computer battery drains to 99% when plugged in!?

Discussion in 'MacBook Air' started by askrib, Aug 23, 2011.

  1. askrib macrumors member

    Joined:
    Apr 15, 2011
    #1
    Hey guys anyone having this problem or know why this would happen?

    I come back to my macbook air i7 256ssd that is plug in that was 100% is now at 99% and i never un plugged it! Whats the deal with this??
     
  2. Mlrollin91 macrumors G4

    Mlrollin91

    Joined:
    Nov 20, 2008
    Location:
    Ventura County
    #2
    Mine does it too, really annoying. My 2009MBP did it as well, but it would then drop to 98% and so on until it reached 94% and recharge itself back to 100%. This process took about a week and a half being plugged in 24/7. My MBA drops to 99% within an hour of reaching 100% and stays there..Doesn't go any lower.
     
  3. GadgetGeek407 macrumors 6502a

    Joined:
    Mar 26, 2009
    Location:
    florida
    #3
    I got my i7 13 tonight haven't charged the battery yet came 88% out the box now have like 26% should i plug it in or don't plug it until totally dead?

    ----------

    btw out of box my cycle count was 0 and now it says 1 and i never plugged it in SMH
     
  4. benhollberg macrumors 68020

    benhollberg

    Joined:
    Mar 8, 2010
    #4
    My MacBook Pro does this all the time. I have it plugged in 99% of the time and it is always running, sometimes it'll go down to like 93% even. I don't think it is that big of deal, well maybe for me because I use it as a desktop pretty much.

    Note though, I have pretty much killed the battery doing this, I can only get about two or 2.5 hours out of it. Sometimes I just let the battery drain while use then plug in to cycle it.
     
  5. askrib thread starter macrumors member

    Joined:
    Apr 15, 2011
    #5
    Thanks. Its good to know I'm not the only one with this.
    But I'm wondering why this happens or if its an OSX bug?
     
  6. ZBoater, Aug 24, 2011
    Last edited: Aug 24, 2011

    ZBoater macrumors G3

    ZBoater

    Joined:
    Jul 2, 2007
    Location:
    Sunny Florida
    #6
    No, this is by design. Keeping the battery at 100% all the time kills it. The system kinda lets it drain a little bit before charging it again to prevent overcharging.

    http://support.apple.com/kb/ts1909
     
  7. askrib thread starter macrumors member

    Joined:
    Apr 15, 2011
    #7
    Oh really? Interesting......Thanks for the data! That makes some sense.
     

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