2012 MBA initial battery capacity not 100% issue !!

Discussion in 'MacBook Air' started by SenorVvangIstMoi, Jun 29, 2012.

  1. macrumors member


    Hey guys.

    I've been using my new Air for a couple of days now and really fallen in love with this beauty. However I realized that the brand new MBA is not shipped with a battery capacity of 100%. I started to worried about it.

    I ran both coconut battery and Battery health since the first boot. The original battery capacity stated on both program are 6700mAh, but my 2day's old MBA currently only has 6598mAh, which is a 2% dropped.. what should I do to prevent this from occurring? Or is it true that every new Macbook computer does not guarantee a full 100% flawless battery?

    Can any apple genius explain this to me please.. I couldn't find any credible result from Google.. Your comments are appreciated.

    Thanks guys!
  2. macrumors 6502a


  3. macrumors 6502a

    My 2010 11" MBA showed 97% when I first got it and I had the same worry. After a few full discharge cycles it went to 98%. It's stayed at 98% for the last two years.

    My new 2012 MBA reads 98% without any discharge cycles. 100% would have been nice but I'm not too worried after my experience with my 2010 model.

    Who knows how accurate the numbers are. All I can say is I get good battery life and that remained true on my last MBA for over two years.
  4. macrumors member


    Thanks for your the link and your confirmation!


    Yup. I agreed with you. There can't be a perfect battery test app out there. And the mid-2012 MBA's battery is truly amazing for its usage under normal stuff such as 8 hours of battery life on low brightness.
  5. macrumors 65816

    my macbook air started out at 95% and fluctuates down to 92%. it never gets above 95%. i was concerned because i started out 5% less than capacity i.e. 15% to 80% not 20%.

    there is a person on here that did a guide for batteries. basically batteries fluctuate.
  6. macrumors demi-god


    It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

    This should answer most, if not all, of your battery questions:
  7. macrumors 65816

    how about if it never fluctuates up? you start at a lower value than 100% which puts you closer to 80% which is replacement.
  8. macrumors demi-god


    If it drops below 80% before 1000 cycles, it's very likely it's defective, in which case Apple will replace it free, if the Mac is still covered by warranty or AppleCare. There isn't a predictable pattern to health decline. For example, it may drop from 100% to 90% in 3 months, then take another year before it drops as low as 85%. Also, just because a battery reaches 80% health or lower, doesn't mean it's a useless battery. It can still be used, even though it won't last as long as a battery with a higher health.
  9. macrumors 65816

    thank you for the good info.

    in your opinion, at what percent less than 100% would you return a macbook that is within its 14 day return policy?
  10. macrumors 65816

    I wouldn't even watch it. It's not a factor. If you are getting horrible battery performance after 11 months, THEN have Apple replace it. Just enjoy the machine.
  11. macrumors member


    o_O! Pardon me, you mean the AppleCare could change new internal opponent for you whenever you went to the service counter within the valid period?!
  12. macrumors regular


    My 2012 13 inch air is doing the same thing. I'm not super concerned about it. The battery capacity increased from 97.7% to 98.8% after a discharge. I just assumed that it was inaccurate.
  13. macrumors demi-god


    If I bought a new Mac and the battery was below 90% when I first got it, I would ask them to check it out and possibly replace it. Above 90%, I wouldn't worry about it. That's what the warranty is for.
  14. macrumors 6502

    Yes. In fact, even AFTER the warranty period, apple will replace the battery for you for a charge. I think it's something like $125for a MBA battery. It's a fairly quick procedure, think mine was done in a few hours since they had parts in stock. (Rev A MBA.)
  15. macrumors 65816

    Yes, if they test it and it is faulty.
  16. tim100, Jul 4, 2012
    Last edited: Jul 4, 2012

    macrumors 65816

    health has dropped to 93%
  17. macrumors 65816

    coconut is now showing 92% battery charge and the apple battery monitor is showing 98%? why are the precent different. the numbers are accurate according to about this mac.
  18. macrumors demi-god


    Take screen shots of both and post them.
  19. tim100, Jul 4, 2012
    Last edited: Jul 4, 2012

    macrumors 65816

  20. macrumors demi-god


    That shows your battery health is 94%.
  21. macrumors 65816

    yes. it is showing different percent left on battery percent coconut is 58% and apple is 61%, is calibration needed?
  22. macrumors demi-god


    No, as stated in the Battery FAQ, your battery time or percentage remaining is a constantly changing estimate, which varies with the current workload on your system at any given point in time. It isn't 100% accurate. The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.
  23. macrumors 65816

    is it normal that coconut battery is showing a different current charge than the battery mac menu bar i.e. the menu bar is showing 5% larger percent left current charge.
  24. macrumors demi-god


    As they are both estimates, taken at particular points in time, it's likely they are taken at slightly different times, causing them to vary, as the workload may differ between one estimate and the other. I really wouldn't worry about it.
  25. macrumors G3


    like others said, i wouldn't worry about it too much. For me, my battery has 1 cycle on it and has 78% health....definitely defective!

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