13" MBA 2012 Battery life dropped

Discussion in 'MacBook Air' started by Ewang1, Mar 23, 2013.

  1. macrumors newbie

    Joined:
    Mar 23, 2013
    #1
    "MaxCapacity" = 5668
    | | "CurrentCapacity" = 577
    | | "LegacyBatteryInfo" = {"Amperage"=3438,"Flags"=7,"Capacity"=5$
    | | "DesignCapacity" = 6700

    Cycles: 357
    8.9month old

    Why???
     

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  2. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    Why what?
     
  3. macrumors 68000

    B...

    Joined:
    Mar 7, 2013
    #3
    Do not rely on apps to tell you battery health. They can be innacurate and fluctuate a lot.
     
  4. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #4
    As you discharged the computer completely 1.3 times per day in the last 8.9 months, you may have led to this by yourself. It is not necessary to discharge the battery daily if you have the ability to connect to power.

    ______________________________________________________
    This should answer most, if not all, of your battery questions:
    Apple Notebook Battery FAQ by GGJstudios
    The F.A.Q. includes the following topics:
    • BATTERY INFORMATION
    • BATTERY LIFE FROM A CHARGE
    • AC POWER
    • CALIBRATION
    • BATTERY LIFESPAN
    • CHECKING STATUS AND HEALTH
    • CHARGING
    • WHAT IS A CYCLE?
    • BATTERIES ARE NOT COVERED
    • BULGING OR SWELLING BATTERY


    ______________________________________________________
     
  5. thread starter macrumors newbie

    Joined:
    Mar 23, 2013
  6. macrumors 65816

    RichardC300

    Joined:
    Sep 27, 2012
    Location:
    North Carolina
    #6
    Sounds right. I'm at 279 cycles and 91% of max capacity.
     
  7. thread starter macrumors newbie

    Joined:
    Mar 23, 2013
    #7
    I see. I thought discharging would help the battery flow better... ( i mean healthier)
     
  8. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #8
    It does not with modern batteries. Read the FAQ I linked to.
     
  9. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #9
    Yes, quite normal.

    The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
     
  10. Ewang1, Mar 23, 2013
    Last edited by a moderator: Mar 24, 2013

    thread starter macrumors newbie

    Joined:
    Mar 23, 2013
    #10
    Thx. Since the data appears on the screen may fluctuate sometimes, is it still possible to restore the battery life to at least 88% if I charging it all the time?
    and if I'm not using my computer, still I keep it charged or leave it plugged in order to make my battery healthier?
    and if I still have, for example, 70% left in my battery, should I plug in to let it recharge to its full capacity while I'm not using my computer( like while my computer is at sleep or shutdown)?

    thx
     
  11. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #11
    If you read the Battery FAQ, your questions should be answered.

    Apple does not recommend leaving your portable plugged in all the time.
    No, you can't restore battery health. Batteries die over time.
    If you don’t plan on using your notebook for more than six months, Apple recommends that you store the battery with a 50% charge.
     
  12. thread starter macrumors newbie

    Joined:
    Mar 23, 2013
    #12
    Thx, my battery life seems to be back after following some of your advise.
    "MaxCapacity" = 6116
    | | "CurrentCapacity" = 6101
    | | "DesignCapacity" = 6700

    It's back to 91.3%
     
  13. macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #13
    It will fluctuate both up and down over time, as previously stated.
     
  14. macrumors 6502a

    Joined:
    Apr 28, 2008
    #14
    To be clear I think what people are saying is that you use your battery a lot so it is natural that the total capacity has decreased. It probably has little to do with HOW you charge and discharge your battery. The sheer amount that you use it is probably outside of the "average" that Apple is considering when they provide their battery health estimates.

    Batteries are a consumable resource. Even if you use your battery perfectly it only has so many charge cycles in it. Not using the battery at all is bad because electrons do need to keep flowing but the more you use it the more you use up the finite resource that is your battery capacity. Plugging in more often will simply slow the rate at which you accumulate extra cycles which in your case will probably slow the degradation of your battery health.

    Still I thank you for presenting this data point because if you can maintain somewhere around 90% battery health with what comes out to 481 cycles/year (if you continue as you are doing now) then my usage (which I thought was quite high) of ~124 cycles/year should be just fine :D

    PS. I highly suspect that the battery capacity that you read in software is an estimate (based on the software's calibration of the battery). I don't think that seeing your battery health go up to 90% means that your battery actually got better (that is actually thermodynamically impossible). It just means the software calibration changed a bit. That is my understanding anyway.
     
  15. macrumors newbie

    Joined:
    Mar 26, 2013
    #15
    Just last week I got a battery service alert for my 2012 MBA. Had less than 250 cycles but health was at around 70%. I took it to the Apple store and they replaced the battery for free. Took about 10 minutes for the whole thing.

    My usage wasn't out of the norm. Used it daily, charged it daily, and let it drain to red once or twice a week.
     

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