2015 MacBook Pro Battery Best Practice - Discharge all the way, or not?

Discussion in 'MacBook Pro' started by Hoff, Mar 13, 2018.

  1. Hoff macrumors member

    Jan 24, 2018
    Hey Everyone,

    Just got a new MBP 2015. Battery is down to 30% on its first cycle.

    Should I run it all the way down to zero% (or close to it), before charging?

    Some people say if you charge it before it's at zero you "train" the battery that it needs to be charged sooner, and the time the battery lasts before needing to be charged again will be less.

    Some people say it's better not to let it go so low. Better to charge it when it's more like 30 or 50%, for example.

    Which of these is true?!? Basically, what's the best treatment for a new battery to keep it powering the laptop for as long as possible each cycle?
  2. impulse462 macrumors 68000


    Jun 3, 2009
    # if cycles is one way to wear the battery so why would you run it down from 30% to 0 when you can just plug it in.

    It’s useful to discharge once in a while but don’t add unnecessary cycles if you don’t have to. Leaving it plugged in at all times however doesn’t necessarily preclude it from diminishing in capacity however
  3. Maxx Power macrumors 6502a

    Maxx Power

    Apr 29, 2003
    Don't run down lithium-based batteries all the way. The shallower the discharge, the more cycles you'll get out of the battery. Keeping it topped off is my best practice. The technical term is "depth-of-discharge", which is the % of total capacity you drain the battery to, per cycle. The shallower this is, the disproportionately more cycles you'll get our of your lithium-based battery.

    See http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries for a detailed explanation.
  4. Hoff thread starter macrumors member

    Jan 24, 2018
    Other people have also said "just use it" and "don't worry about it." So yeah, instead of worrying about it for 3 years, I will just use it and spend the $200 to replace it if/when it wears out.

    But in the mean time, your guys' answers are a real help. Great feedback. I won't put any more cycles (or deeper cycles) on it than I need. Thank you!
  5. Queen6, Mar 16, 2018
    Last edited: Mar 16, 2018

    Queen6 macrumors 604


    Dec 11, 2008
    Flying over the rainforest at dawn - Priceless
    Deep discharging the battery is the fastest way to kill cycles, just use and enjoy the notebook. The hardware & OS will manage the battery perfectly well. Only time user intervention is really needed is if the notebook is plugged in permanently, then it's prudent to run the computer on battery once a month allowing it to drop down by only 10%-20% to "exercise" the cells.

  6. Hoff thread starter macrumors member

    Jan 24, 2018
  7. robvas macrumors 68030

    Mar 29, 2009
    I wouldn't make it a habit of running it lower than 10%

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6 March 13, 2018