How to set Mac so that it does not charge until the battery is below 75%?

Discussion in 'macOS' started by eswee, Dec 14, 2014.

  1. eswee macrumors newbie

    Joined:
    Dec 14, 2014
    #1
    It is my first Macbook. I don't want to charge it too often so the battery performance decreases. With my old PC laptop, I switch between the battery and external power all the time, but it only charges once in a while when the battery has less than 75%.

    I don't want the Mac to charge when there is 98% battery left - anytime after I take it to the balcony to have a coffee or into the bathroom to watch a video while doing number 2. Correct me if I am wrong, but after every charge the performance of the battery decrease a little (retain 80% after 300 charges according to information I found online.)
     
  2. Dave Braine macrumors 68040

    Dave Braine

    Joined:
    Mar 19, 2008
    Location:
    Warrington, UK
    #2
    Don't plug it in to the wall then. Simple. There's no way to do what you want, AFAIK.
     
  3. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #3
    You've made at least two errors:

    1. A "charge" and a "cycle" are not the same thing.
    2. The upper limit isn't 300 cycles (note: cycles, not charges) unless your computer is several years old.

    http://support.apple.com/en-us/HT201585
    ... A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could use your notebook for an hour or more one day, using half its charge, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so it may take several days to complete a cycle.​

    https://www.apple.com/batteries/service-and-recycling/
    Your battery is designed to retain up to 80% of its original capacity at 1000 complete charge cycles. ...​

    http://support.apple.com/en-us/HT204054
    ...
    My battery will not charge to 100%
    Occasionally, the battery may not show a full charge (100%) in OS X, even after the power adapter has been connected for an extended period of time. The battery may appear to stop charging between 93 percent and 99 percent. This behavior is normal and will help to prolong the overall life of the battery.

    The first article linked to above also has a table of older models and their cycle count limits. 300 cycles was the typical limit in 2008-2009.
     
  4. eswee thread starter macrumors newbie

    Joined:
    Dec 14, 2014
    #4
    Thank you. This is very helpful information.

    Although there seems to be no resolution to what I wanted to do, now it seems less important...

     
  5. Dave Braine macrumors 68040

    Dave Braine

    Joined:
    Mar 19, 2008
    Location:
    Warrington, UK
    #5
    Just for info, I have a White MacBook. The Mac and it's battery are 6 years old. The battery has 661 cycles, charges to an indicated 100%, and coconutBattery says it charges to 76% of it's original capacity.
    http://www.coconut-flavour.com/coconutbattery/
     
  6. Fzang macrumors 65816

    Fzang

    Joined:
    Jun 15, 2013
    #6
    My rMBP has the following stats:
    Battery is 431 days old
    97 load cycles
    97.4% of maximum capacity

    What you're doing, OP, is completely irrelevant :rolleyes:

    Currently, with 89% charge remaining I still have 7:30 hours of "light usage" remaining. Imagine having to deplete that 300 times, just to get down to 80% of original capacity.
     
  7. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #7
    Your battery will not charge if you plug it in between 93-99%. It is designed to avoid such short discharges/recharges. You don't need to worry about doing anything to intentionally manage your battery. Your Mac will do that automatically. 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.
    If you bought a new Apple notebook, it's designed to retain up to 80% capacity for up to 1000 cycles. For some older Mac notebooks, the threshhold was 300 or 750 cycles. See the Battery FAQ for details.
     
  8. AlecZ macrumors 65816

    AlecZ

    Joined:
    Sep 11, 2014
    Location:
    Berkeley, CA
    #8
    People have told me that charging a rechargeable battery too frequently reduces the life. Apple's user manuals deny that. Also, as said above, charging it once does not use an entire charging cycle. I always thought it was best to charge whenever possible.
     
  9. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #9
    Charging it once may use an entire cycle if it was fully discharged. See the WHAT IS A CYCLE? section of the Battery FAQ for details. 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.
     

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