Extremely Slow when battery is 0%-1%

Discussion in 'MacBook Pro' started by alco933, Feb 29, 2016.

  1. alco933 macrumors newbie

    Joined:
    Feb 29, 2016
    #1
    I am using a MacBook Pro for work and have never used one before. It's really nice but one major quirk it seems to have is that I will set it to standby on Friday afternoon and then I start it again on Monday it will sometimes be completely drained and sometimes it will have about 50-70% battery left. I'm not understanding the wide disparity of remaining charge times for the exact same periods of time every week.

    Also , on the times it goes down to 0% , it is unusable , even when plugged in, until it gets up to about 2-4% and is very slow. I can't even log in if it is 0% battery when plugged in.
    It seems like it is always operating on battery even if it is plugged in.

    I would expect that when you plug something in , it should run like a normal laptop would.

    Are these things typical?
     
  2. joe-h2o macrumors 6502a

    Joined:
    Jun 24, 2012
    #2
    No, there is something wrong if those are typical results.

    Reset the SMC and see if it improves the behaviour.

    If it is running flat over the weekend then then computer is waking up for some reason and not returning to sleep until the battery drops right down.

    The system should force the machine to sleep at well above 0% charge, so if it is not doing that then you need to investigate. Does it have any third party kernel extensions installed?
     
  3. alco933 thread starter macrumors newbie

    Joined:
    Feb 29, 2016
    #3

    Thanks for the quick reply.
    But not understanding "SMC" as a new MAC user. Preferences or something?
    Same for "kernel extensions installed". Applications?
     
  4. JohnDS macrumors 65816

    Joined:
    Oct 25, 2015
    #4
    Reset SMC: https://support.apple.com/en-ca/HT201295
    --- Post Merged, Feb 29, 2016 ---
    Also in your system prefs under Energy Saver, under Battery, check "put hard drives to sleep when possible" and uncheck "power nap".
     
  5. alco933 thread starter macrumors newbie

    Joined:
    Feb 29, 2016
    #5
    Already had those set that way.
     
  6. aimbdd macrumors 6502a

    Joined:
    Dec 10, 2008
    Location:
    East Cost
    #6
    The computer being slow while at 0-1 % is normal. The computer is self throttling as to not over draw the computer. The charger doesn't provide enough energy to run the computer at 100% load which is why it doesn't return to normal even while plugged in until it's up to 2%. It needs a buffer. So the battery doesn't run out and the computer turn off.
     
  7. Udi macrumors newbie

    Joined:
    May 22, 2008
    #7
    aimbdd is correct, this is normal behaviour.

    Furthermore, draining the battery to below 10% (particularly 0-1%) isn't good practice on any modern Lithium battery. Doing this regularly will permanently reduce the battery capacity over time, Lithium Polymer chemistry prefers to be in the 20-80% charge range for maximum longevity. This is also the reason Apple recommend that the charge level is set at 50% for long term storage - it's no coincidence that this is the median value of aforementioned range.

    So if you care about maximising battery life, it's a good idea to avoid draining completely flat unless absolutely necessary - and in doing so you'll avoid your issue also.
     
  8. Ovedius macrumors 6502

    Ovedius

    Joined:
    Aug 2, 2012
    Location:
    Norway
    #8
    I always assumed it was a combination of throttling av backuping important system stuff so that you could resume where you left off once you power it up again.
    Of course, I know absolutely ZILTCH about these things so I just do what I always do; draw ignorant, half-assed conclusions.
     

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