"Battery time remaining" going crazy

Discussion in 'MacBook Air' started by kinkster, Feb 14, 2009.

  1. kinkster macrumors 6502a

    Joined:
    Sep 15, 2008
    #1
    I have a Rev A 1.6/80.

    Just running on battery, the estimated time remaining is normal. About 4:00 with a 97% charge.

    But when I have it plugged in, it goes really low. About 20-14 minutes. I know I have an almost full charge and the battery isn't shot or anything because I just used it for about 3 hours yesterday without plugging in. Even with the innacurate estimate it still reports the % correctly.

    The iStat widget reports similar numbers, but not exactly the same. 16 on it, as opposed to 13 in the menu bar.
     
  2. tingly macrumors 6502

    Joined:
    Apr 27, 2005
    #2
    That could be the charging time, up to 100% charged in 14-20 minutes
     
  3. kinkster thread starter macrumors 6502a

    Joined:
    Sep 15, 2008
    #3
    I was thinking that before but it's always showed the time remaining before. Or maybe when it's plugged in it would just show "charged" I don't remember really.

    It slowly went down to 5% then went back up to 9%, with iStat saying "remaining: unknown"
     
  4. Constantinos macrumors newbie

    Joined:
    Mar 15, 2008
    Location:
    Athens, Greece
  5. clawanhex macrumors member

    Joined:
    Oct 18, 2008
    #5
    It's not to be unexpected...

    This is an acknowledged problem (or feature, I'm not sure) of the MacBook batteries. The MacBook batteries don't charge unless they're around 95% charge, and the machines tend to get funny readings when they're at this high mark - the machine rarely takes an accurate reading.

    If you're still worried, you can try:
    • Calibrating the battery
    • Resetting the SMC (System Management Controller).

    Instructions for either can be found with a quick Google search.
     
  6. kinkster thread starter macrumors 6502a

    Joined:
    Sep 15, 2008
    #6
    oh good to hear. thought i was going to have to mention it if I try to resell it some day.
     

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