Battery going downhill?

Discussion in 'MacBook Air' started by zRedbullz, Aug 17, 2011.

  1. zRedbullz macrumors regular

    zRedbullz

    Joined:
    Sep 12, 2006
    Location:
    UK
    #1
    Hey guys,

    My 10 month old Macbook Air (2nd Rev), is showing a battery charge capacity of 89% (5999) out of 6700 mAh, which sounds a rather rapid deterioration to me.

    Am I alone in losing 11% of my charge in less than 10 months?, losing 1% a month?

    Cheers
     
  2. PaulWog Suspended

    Joined:
    Jun 28, 2011
    #2
    Apparently it's normal to see this sort of thing. If you're super worried, take it in before your warranty is up and see what a Genius rep has to say.

    Really what you should be looking at more-so than how long you've owned the Macbook Air is how many battery cycles you've gone through so far. The Air is designed to reach approximately 80% battery life after 1000 cycles, and if it averages out lower than 80% battery life before 1000 cycles is up and you're still in warranty, it is I believe considered defective (no normal user can use up 1000 cycles in a year, so you'd have to be on the AppleCare plan to pull a warranty claim on that).

    You'll see more rapid degradation of battery life at first, and it will reach 80% much more slowly as it gets closer and closer to 80% (that's what I understand).
     
  3. meaty macrumors member

    Joined:
    Feb 27, 2011
    #3
    i got the 2011 air i7 13" first day it came out and im at 6505 of 6700mah (97%) battery life doesnt seem that long and i never have the brightness above half. is this norm?

    (sorry didnt want to make a new thread)
     
  4. aeboi macrumors 65816

    aeboi

    Joined:
    Sep 20, 2009
    Location:
    Bay Area
    #4
    yes it's normal, there are plenty of battery related threads, just use the search function
     
  5. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #5
    If you haven't taken the steps to calibrate your battery, you should do so. You will find how to do it by searching here, or on the Apple support pages.
     
  6. meaty macrumors member

    Joined:
    Feb 27, 2011
  7. ftored macrumors regular

    ftored

    Joined:
    Dec 29, 2005
    #7
    I noticed too that on my MB air 11' first gen battery life really got down lately.

    I blamed the upgrade to Lion though and haven't checked how much % shows in system prefs. Will wait to see the first updates of Lion if it fixes it up a bit and then taking it to Apple
     
  8. zRedbullz thread starter macrumors regular

    zRedbullz

    Joined:
    Sep 12, 2006
    Location:
    UK
    #8
    *UPDATE*

    Calibrated the battery a couple of times - made not one bit of difference to the percentage.

    The battery capacity has now dropped 1% to 88%

    Surely there is something wrong with the battery? Booked a Genius bar appt for tomorrow - do i need to be on AppleCare to pull a warranty claim then?
     
  9. yuanmoons macrumors 6502

    Joined:
    Aug 7, 2008
    #9
    you are within the first year so no need for applecare etc. the serial number will tell them the age of the mba.

    let us know what happens.

    good luck.
     
  10. flight macrumors regular

    Joined:
    Mar 4, 2010
    #10
    Don't calibrate too often. As far as I know, calibration is done for better estimates on battery life - not to improve battery life itself. Frequent deep discharges are harmful for your battery.

    Do you often let the battery go below 10% before plugging in? If so, that might be one reason for your issue.
     
  11. bizzle macrumors 6502a

    Joined:
    Jun 29, 2008
  12. iphonsteve4ajob macrumors regular

    Joined:
    Aug 6, 2011
    #12
    +1

    ----------

    You are correct, calibration does not improve battery life. However, a "deep discharge" will not harm your battery. There are system monitors in place which put your system to sleep at 0-1% charge (small reserve power remaining) to prevent a total discharge. Apple's calibration guide suggest a 5hr sleep (no charger connected) before re-charging.

    Now if you were to leave your laptop in this state and not plug the charger in for a few weeks, then your battery will completely discharge and potentially decrease its full charge capability.
     
  13. flight macrumors regular

    Joined:
    Mar 4, 2010
    #13
    Ars Technica claims that frequent discharges below 20% does in fact harm your battery. However, they did not provide a source for the information. I've seen the 20% and 10% figures quoted from different places so I don't really know who to believe.

    If what you say is true, then I can breath a sigh of relief. :p I've always put the don't-discharge-below-20% rule into consideration when judging battery life figures from manufacturers. For example, Apple claims 5 hours for the MBA11, so I see it as 4 hours.
     
  14. iphonsteve4ajob macrumors regular

    Joined:
    Aug 6, 2011
    #14
    Yeah I actually don't let mine run down past 20% most times also. I've also read many different claims regarding batt life reduction if you let it run down. But the point I was making is that you can't run it down to complete 0.00% unless you let it run down, go to sleep, and never plug the charger back in.

    From Apple's Batt website >

    Tip: When the battery reaches "empty", the computer is forced into sleep mode. The battery actually holds a reserve beyond "empty", to maintain the computer in sleep for a period of time. Once the battery is truly exhausted, the computer is forced to shut down. At this point, any open files could be lost. Therefore, it is important that you find an electrical outlet and connect the adapter before the forced shutdown occurs.
     
  15. zRedbullz thread starter macrumors regular

    zRedbullz

    Joined:
    Sep 12, 2006
    Location:
    UK
    #15
    89 - very low

    ----------

    I was not aware that I needed to re-charge at 20%. I re-charge at various times, sometimes as low as 5% or 35%, all depends on what I'm doing and where I'm going

    I'm surprised by the fact that the battery is losing over 1% every month. At this rate, it'll be under 80% come this time next year.
     

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