battery question

Discussion in 'MacBook Air' started by Rhcpcjg, Apr 27, 2015.

  1. Rhcpcjg macrumors regular

    Joined:
    Sep 19, 2014
    #1
    Today I purchased a macbook air, I've owned several MacBooks before but this is my first air. I just finished fully charging the battery, and it says i have close to 14 hours remaining of battery life. My question is, is this number accurate? or I just need to give the computer a couple of days to calibrate the battery. I usually get 6 hours on my rMBP 15' so this 14 hour estimate seems unrealistic to me... or who knows, maybe the MBA's battery is as good as they say it is.
     
  2. ozziegn macrumors 6502a

    ozziegn

    Joined:
    Aug 16, 2007
    Location:
    Central FL Area
    #2
    I just bought a 13.3 MBA. I fully charged the battery and I've been using the laptop for roughly four hours and I have 59% left or 4.25 hours remaining according to the battery meter. I do have my screen brightness at like 90% which I'm sure is hurting my battery runtime some but I'm okay with that. I will be happy with anything of 8 to 9 hours on a single battery charge.
     
  3. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #3
    Those estimates are just that--estimates. How much battery life you get depends on a million different things. The only good way to see how much you will get is to actually use the computer on battery power for doing typical tasks and see how long it lasts.
     
  4. vanimal macrumors 6502a

    Joined:
    Sep 12, 2014
    #4
    I bought a 2015 MBA 13" as well last week. I only have like 4 cycles but yes mine after the last charge showed as high as like something crazy like 18 hours lol. :eek:

    But again its a estimate, should have no problem getting 11 plus.
     
  5. kohlson macrumors 6502a

    Joined:
    Apr 23, 2010
    #5
    You probably need to calibrate the battery/charging system. Run it all the way down until it turns itself off (find a YouTube Movie). Charge it all the way up in one session, then run it all the way down again. Then charge it up. The system will then know the upper and lower limits of the battery.
     
  6. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #6
    No. This may or may not have been a good thing to do before but it isn't now. It will just put wear on your battery for no reason and it will do the opposite of calibrating. The system will conservatively decrease the charge capacity of the battery and it will take a while to get back to normal.
     
  7. itsmefudge macrumors regular

    itsmefudge

    Joined:
    Jun 10, 2009
    Location:
    Middle of the Pacific
    #7
    So what is the best way? I just bought a new 2015 13" Air and it only has 1 load cycle. At 100% charge, it says I only have 6+hrs of battery. I thought I was suppose to get "up to 12hrs" I am no where near that number.
     
  8. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #8
    They come calibrated from the factory. Your just paying to much attention to the meter that's all. It fluctuates massively depending on the current task.
     
  9. pol0001 macrumors 6502

    pol0001

    Joined:
    Apr 15, 2008
    Location:
    London
    #9
    I also bought a 2015 13" MacBook Air recently. This is my experience so far:

    - If I don't use too taxing apps (Excel, Mail, Evernote etc.) I get at least 10 hours out of the battery.
    - Google Hangout video chats use a lot of power.
    - After restarting or waking up the computer, the battery estimate needs some time to give a realistic forecast. For example: When I started my MacBook Air yesterday morning, the estimate was 4 hours. But within 45 minutes of use, the estimate went up to 9 hours.
     
  10. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #10
    Again, that's only an estimate. And it's based on what you've been doing with the computer over the past minute or so. You must have been doing something CPU intensive. Let the computer relax and it will show you a bigger number.

    Battery time will vary wildly on what you do with the computer. Turn off wifi, turn down the screen brightness, and just type stuff into TextEdit and you'll get like 20 hours. Turn up the screen brightness, max out the CPU and GPU, and download something on wifi and you'll run the battery down in 2-3 hours.
     
  11. Newtons Apple macrumors G5

    Newtons Apple

    Joined:
    Mar 12, 2014
    Location:
    Jacksonville, Florida
    #11
    The indicated time for the battery reflects what the laptop is using at the time. If you turn up brightness and start playing a video the amount of time left on the battery will change.

    The battery gauge is dynamic and changes all the time. It is only a guide and not an exact number.
     
  12. itsmefudge macrumors regular

    itsmefudge

    Joined:
    Jun 10, 2009
    Location:
    Middle of the Pacific
    #12
    Yes, I get that. I meant, the best way to preserve the life of the battery- some say run it down and others say do not. I have always been in the camp of running it down once a month or so till dead- then charging without using it until it is fully charged- I am sure I read it somewhere years ago, so I guess I just thought that was the correct way. It has always been good for me in iPhones, iPads, iPods, laptops, etc. I am willing to change if someone has a better way...

    Thoughts?

    ----------

    Also an update, after updating to 10.10.3 and repairing permissions I am at 11:33 on the battery. :) Yes. I know it's just an estimate.
     
  13. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #13
    Apple used to recommend running the battery down once a month. I don't think there was any specific idea about how it should be recharged. They stopped recommending this a couple years ago though. Who knows if they decided it's no longer necessary, or if it's bad for the batteries, or if the advice was being misunderstood/misinterpreted by people, or what.

    Personally I keep my 2014 MBA plugged in whenever possible. Now that batteries last as long as they do, I probably go months at a time without the charge dropping below 75%. (I just use the laptop once in a while at coffee shops on battery power, and it's not like I can sit there for 9 hours straight.) So far my battery is a year old and still in perfect condition so I don't think this is bad for it.
     
  14. itsmefudge macrumors regular

    itsmefudge

    Joined:
    Jun 10, 2009
    Location:
    Middle of the Pacific
    #14
    Sounds good. Thanks. Looks like I need to buy another charger cable to keep at work. I hate dragging those things with me.
     
  15. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #15
    The time remaining is a constantly-changing estimate, based on the minute-to-minute power demands of your computer. It is not accurate, as you won't maintain the same level of power demands throughout the life of a charge.
    That is not calibration. Doing what you suggest puts cycles on the battery needlessly and isn't good for the battery. It will not "calibrate" the battery or have any effect on the battery's function. The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries in older Apple notebooks.

    There are many factors that impact your battery life. See the BATTERY LIFE FROM A CHARGE section of the following link for details, including tips on how to maximize your battery life.
    Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug any time you need to, regardless of the charged percentage, and you never need to completely drain your battery.
    The link below should answer most, if not all, of your battery/charging questions, including tips for maximizing battery performance. If you haven’t already done so, I highly recommend you take the time to read it.
     

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