Terrible battery life ML mba 2011

Discussion in 'MacBook Air' started by shadowjeff, Jul 26, 2012.

  1. shadowjeff, Jul 26, 2012
    Last edited: Jul 26, 2012

    shadowjeff macrumors regular

    Aug 3, 2010
    I just recently upgraded from lion to mountain lion on my 13 inch macbook air 2011 and i realized a significant drop in battery life. When i was on lion, my average battery life was around 5 hours but now with mountain lion it significantly decreased to 2 1/2 - 3 hours (Doing the same tasks and on the same brightness).

    Anyone experiencing the same issue and any solutions that i could try? If nothing else works i might just bring it to the genius to have it check upon.

    I've looked at GGJStudio's battery life guide: http://forums.macrumors.com/showpost.php?p=9875442&postcount=23 but it didn't help.

    My battery health : 87% and with 237 charges.
    Looked up activity monitor and realized kernel_task taking up about > 15% cpu and using up 300 mb of ram

  2. GGJstudios, Jul 26, 2012
    Last edited: Aug 3, 2012

    GGJstudios macrumors Westmere


    May 16, 2008
    1. Launch Activity Monitor
    2. Change "My Processes" at the top to "All Processes"
    3. Click on the CPU column heading once or twice, so the arrow points downward (highest values on top).
    4. Click on the System Memory tab at the bottom.
    5. Take a screen shot of the entire Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
    6. Post your screenshots.
  3. shadowjeff thread starter macrumors regular

    Aug 3, 2010
    Thanks for the reply! Here are the screenshots

    Attached Files:

  4. GGJstudios macrumors Westmere


    May 16, 2008
    I don't see anything there that indicates significant load on system resources. Are you going by actual uptime on battery until it dies, or by the time remaining indicator?
    From the BATTERY LIFE FROM A CHARGE section of the Apple Notebook Battery FAQ:
    By the way, your kernel_task process is part of Mac OS X, and it looks normal.
  5. drxcm macrumors regular

    Nov 2, 2010
    Interesting - I was about to post the opposite!

    I have a 2011 11" 1.8 i7 - just installed ML yesterday.

    Spent 3 hours doing powerpoint presentations, mid-brightness, listening to iTunes on the plane yesterday, and only lost 35% of battery life. I was amazed. In saying that, no wifi etc.
  6. shadowjeff thread starter macrumors regular

    Aug 3, 2010
    I'm actually looking at the time remaining indicator as comparison but when i was running lion, it used to show 5 hours and my mba actually lasted roughly 5 hours in real time. This was on about medium brightness

    I haven't really got the chance to conduct a run down test with mountain lion yet. Currently i've used the laptop for 40 mins (mostly idle for downloading) and it went down by 25% so based on this estimate, my battery life will only last for 2 hours 40 mins. Have been using this mba on 1 bar to 1/4 brightness.


    I'm surprised because i wasn't doing anything cpu intensive, actually i was leaving my mba on just to download stuff while i'm studying and it went down 25% in just 40 minutes!
  7. RolledUp20s macrumors regular

    Jun 14, 2011
    Wrexham, North Wales
    I have the mac air 13'' mid 2011, 120GB, 4GB RAM.. think thats the same as yours ye?
    anyway, ive not noticed a drop in battery life and out of curiosity i checked my Activity monitor. my kernel_task doesn't go above 2.5%cpu - i see yours is 17.5% ...so, is it that?
  8. Satnam1989 macrumors 65816

    Nov 16, 2011
    I'm facing similar issues, Do your fans spin up high when you launch any of the following:
    - Notes
    - Game Center
    - iWorks (Pages, Numbers or Keynote)
    - Mail.app
    - Reminders

    For me there is a process called "ubd" that appears each time I open one of these apps and it sits around for a good number of minutes using HIGH CPU and my Fans spin like crazy at 5000-6500RPM even when temps are <80....finally it goes away or I have to force quiet it not once but many times if I want it to go away faster.

    It is the only process that is taking up power, also I noticed Skype is causing fans to spin alot sooner while doing video chat than it did in Lion but then again it hasnt gotten a update for ML yet.

    details of ubd process: It is a iCloud sync related process, it continuously creates com.apple.ubiquity.peer.uuid key and certificate files in KeyChain Access (at least on my machine)...up to 25,000 key and certificate files contianing com.apple.ubiquity.peer.uuid ending with random letters (seem to be for each time it estabilishes a connection with iCloud..)

    I originally faced the issue with I upgraded but then I did a clean install and the problem remained....
  9. dyn macrumors 68030

    Aug 8, 2009
    What GGJstudios guide doesn't tell you is to look into things like the GPU (videocard) and the disk (hdd in particular) as well as the optical drive. You can see what the disk is doing (amount of MB/s read/written and even the iops (i/o operations per second or simply put how many times it is reading/writing per second)). Whenever you install a fresh copy of OS X or upgrade it Spotlight will refresh its index causing quite a lot of iops which means that it is extensively using the disk to read and write. Other things like rebuilding the caches can cause it as well. That is why the disk also matters.

    Some apps that don't work that well with the new OS might cause something like that as well so be sure to update everything on your machine.

    Another thing to do is let it settle for a while. Sometimes it just needs some time to get settled/calibrated. If you want you can reset the SMC and/or recalibrate the battery if you want to be really sure and speed things up. I'd wait a few more days and let the dust settle (figure of speech).

    OS X Mountain Lion has changed the algorithm for calculating batterylife iirc. It now calculates it differently which should be a bit more accurate. This can cause a different time given than you expect. Do keep that in mind as well.
  10. buddybd macrumors 6502

    Jul 28, 2011
    I've been using the GM and so far I have no issues. Did you do a clean install?

    It could be Spotlight was indexing files or some other background stuff after a new installation.
  11. Satnam1989 macrumors 65816

    Nov 16, 2011
    My MBAir was on all night last night and all day today so it had plenty of time to index. Also I did see a Indexing bar in the spotlight, and I did go into spotlight later on today to uncheck some of the things I dont need it to be donig as I use alfred.

    But the heating/intense CPU issue and the high fan spinning for me only happen if and when I launch any one of the following: Notes, Pages, Numbers, Keynotes, Game Center or TextEdit. But its not the individual apps that are driving my MBAir crazy its the ubd process.....again I'm just really shocked that I have spent almost 24hours on this forum checking constantly but have yet to find a single person experiencing same problems as me.....w/ ~1500 members active at almost all the time.

    PS Shadowjeff I dont mean to take over your thread with my issues, hopefully we can all solve some if not all of these issues in one way or another:)
  12. shadowjeff thread starter macrumors regular

    Aug 3, 2010
    I tried those apps you mentioned and i didn't run in to any high cpu usage or fan usage, seems to be running fine for me. Haven't really tried video calling using ML yet but even on lion it runs pretty hot for me.


    Yea i will try resetting the SMC again to see if it's better. I installed ML yesterday so spotlight indexes should be done by now, and i don't see any dot in the spotlight icon so i doubt it's indexing.
  13. scarred macrumors 6502a

    Jul 24, 2011
    My battery had to be calibrated after ml was installed. It kept thinking I had four hours of power left, for a good while. Then it dropped and stuck around two. The last ten minutes took an hour.

    Could that be your issue as well?

Share This Page