Leave it plugged in?

Discussion in 'MacBook Pro' started by Dcuellar, May 2, 2010.

  1. Dcuellar macrumors regular

    Feb 24, 2010
    I was wondering if leaving my laptop plugged in is alright or should I stay away from doing that? Are there any confirmations that it does or does not hurt your battery life?

    I tend to just leave it plugged in, but if it's proven to hurt the life of the battery I will change my habits.
  2. millertime021 macrumors 6502a


    Jan 28, 2010
    From what I've heard, from the forums and such, it's best NOT to leave it plugged in all the time. Try to unplug it, even if you are at your desk. It helps the battery cycle and such.

    I wouldn't be too paranoid about it, just use it how you prefer.
  3. thecheda macrumors 6502

    Apr 9, 2006
    Los Angeles

    This is also something that I have been wondering about. I have always received conflicting answers to what is best for the battery life.
  4. vant macrumors 65816

    Jul 1, 2009
    I haven't found any information yet.

    Logically, I don't see anything wrong with leaving it plugged in. Battery life is affected when energy is taken and placed back. When you leave it plugged in, the battery is bypassed (assuming it is charged).

    You don't accumulate cycles when it is plugged in and fully charged.
  5. stevefrog macrumors newbie

    May 2, 2010
    You should leave it plugged in. There will be no damage done by doing so. The computer has its own charging circuitry to prevent overcharging.

    The reason so many people think it's bad is because of misinterpreting Apple's suggestion of running down battery every once in a while. The reason to run the battery down is to calibrate the software battery meter. If the battery is not used often, the battery meter gets out of sync with the battery's charge state. For this reason, it's good to use the battery once in a while.

    Leaving the computer plugged in (and lever running the battery down) simply causes the battery meter to become inaccurate. Running the battery down recalibrate the meter. Constantly running the battery down and recharging it simply reduces the battery's life.

  6. JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
    I see your point about misinterpretation and I think you are partly right, but I believe your post is contradicting Apple's recommendations:

    See http://www.apple.com/batteries/notebooks.html
  7. Readover macrumors member

    Apr 16, 2010
    It is recommended to go through at least one cycle per month to keep the battery good. As simple as that.
  8. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    Apple's recommendation in this regard are useless, or at best unjustified. "Keeping the electrons moving?" Science fail.

    I've had laptops that have remained plugged in more or less all the time and they've been fine. I've had laptops that cycle once every 1-2 days and they've been fine also. Just use your machine in the way that's most convenient for you.
  9. scaredpoet macrumors 604


    Apr 6, 2007
    Right, sooooo we're to assume that you, Random Internet Guy, know more than Apple does about their batteries. Do you have an EE or something to back up your assertions?

    Generally, when one discharges a battery, electrons are in fact, moving.


    Or, are we to blindly trust that you, Random Internet Guy, also knows more than practically all contemporary physicists out there, too?

    For me the bottom line is this: I'm going to go with Apple recommends because ultimately, they made the laptop and they're the ones that will either fix a bad battery or raise a stink that it wasn't used properly. When my laptop has "miles01110" on the bezel, then I'll follow your recommendations.
  10. Hellishness macrumors 65816


    Jan 27, 2010
    Bay Area, CA
    Leaving it plugged in will kill you battery faster than plugging it about half the time. Just maybe unplug it at night, and whenever you remember to do it while using it. The batteries last a long time an give you sufficient warnings when it is running low.
  11. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    What good does me saying I have an EE degree do? As if you'd believe me. Don't fool yourself- you've already made up your mind on this one.
    Generally electrons are always moving.


    Do what you want. I've satisfied my curiosity with experiment and have concluded that any "gain" in battery life you might get from enslaving yourself from an unnecessary calibration schedule far outweighs the inconvenience of doing so.
  12. ARF900 macrumors 65816


    Oct 30, 2009
    Its fine as you long as you calibrate once a month. (IMO)
  13. grndfthrprdx macrumors newbie

    May 1, 2010
    "Movement" is harder to define if you are thinking about things in terms of quantum mechanics. Electrons no longer have a position and a momentum. dP(x)/dt or dP(xbar)/dt would be the things that might change. But, not all quantum electrons have to be moving according to these definitions. Although, in a battery, the conduction band electrons would be. The inner electrons would still be in roughly stationary states. :)

    I tend to agree with your take on charging though.
  14. wilycoder macrumors 6502

    Aug 4, 2008
    What a pity you are posting on the internet instead of building batteries for apple :rolleyes:
  15. AreYouIn? macrumors 6502a


    Jun 9, 2009
    Well I have a 2007 macbook that has 979 loadcycles and is still at 95% health. I let it charge completely then I unplug it and plug it back in when it gives me the warning. Occasionally i leave it plugged it.

    It works for me.
  16. capitanbuzo macrumors 65816

    Jul 17, 2007
    Yeah. Probably better to let it drain every month. I have a 2007 Macbook Pro with 48 cycles on it. 82% battery health. Calibrated it two days ago. I leave it plugged in a lot and not really in use (use my Mac Pro and other computers mainly atm).
  17. scaredpoet macrumors 604


    Apr 6, 2007
    I would certainly respect your opinion a bit more.

    Only in that Manufacturer's recommendations > Random Internet Guy with nothing to back up his assertions of "science fail."
  18. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    Ok, I have an EE degree.

    ...except experimental results that render the manufacturer recommendations inconclusive at best.

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