"Battery time remaining" going crazy

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

  1. kinkster macrumors 6502a

    Sep 15, 2008
    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

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

    Sep 15, 2008
    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

    Mar 15, 2008
    Athens, Greece
  5. clawanhex macrumors member

    Oct 18, 2008
    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

    Sep 15, 2008
    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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