Charged/Percentage Discrepancy

Discussion in 'MacBook Pro' started by Fujikon, Apr 26, 2010.

  1. Fujikon macrumors member

    Joined:
    Jun 17, 2007
    #1
    When I switch between displaying "time" and "percentage" on my battery indicator on the upper right of the screen - I see "charged" for time and "99%" for percentage. Shouldn't it say 100% if it's fully charged? My MBP is only a couple of days old by the way.
     
  2. jmcclain145 macrumors regular

    jmcclain145

    Joined:
    Jul 27, 2008
    Location:
    Atlanta, GA
    #2

    This may not be the best answer, however my three Previous MacBooks all did the same thing.

    I've had a 13" mid 2009 Pro, 15" mid 2009 Pro and currently a 15" mid 2010 pro.

    It maybe because I haven't followed Apples discharge and recharge battery guide. I still get a solid 6-7 hours depending on the preferences I have turned on, so I'm not to concerned.

    Is your battery life being affected?
     
  3. Fujikon thread starter macrumors member

    Joined:
    Jun 17, 2007
    #3
    I have not fully tested the battery life yet.
     
  4. jmcclain145 macrumors regular

    jmcclain145

    Joined:
    Jul 27, 2008
    Location:
    Atlanta, GA
    #4

    Again, you should be fine, as I mentioned my Mac's have all done this as well and none of them suffered battery life.

    If your really worried, try the 100% charge, then remove from power source, let battery deplete ALL the way and leave powered off for I believe 5 hours, then charge fully again.

    http://support.apple.com/kb/HT1490

    I googled the issue, and what I read, it seems to be a calibration thing. Follow the steps in the link posted and all should be good, I'm going to do the same on my new Pro today! :)
     
  5. Pax macrumors 6502a

    Joined:
    Dec 12, 2003
    #5
    If you fully charge the battery, then run it down a small amount (a few percent) it won't charge it back up again. This is for complicated technical reasons to do with battery longevity.

    IIRC the magic number is 95%. If you discharge your Mac down to 96%, it will sit at 96% forever until you discharge it below 95%. Then it will charge back up to 100%.

    So I think your behaviour is normal.

    You can check by using your Mac on its battery for 15 minutes or so, until it has dropped below the magic 95% (if that's the right number). Then if you plug it back in it should charge back up to 100%.

    I think this is written up somewhere on the Apple site.
     
  6. Fujikon thread starter macrumors member

    Joined:
    Jun 17, 2007
    #6
  7. mixvio macrumors 6502

    Joined:
    Apr 12, 2009
    Location:
    Sydney, Australia
    #7
    This.

    Rechargeable batteries naturally discharge over time, and it actually hurts the battery life for the computer to maintain it at a consistent 100% all the time.

    It's very common for laptops these days to leave it discharging once it's hit 100%, until the battery's charge drops below a certain point.

    It's perfectly normal and all laptops do this, not just Apple.
     

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