Battery cycles. How does it work?

Discussion in 'MacBook Air' started by pmichellon, Mar 10, 2010.

  1. macrumors newbie

    Mar 3, 2010
    Dublin, Ireland

    I bought a Macbook Air 2 weeks ago and I'm very happy with it. I don't even turn on my pc anymore :eek::D

    Still there's one thing I don't understand. How do the battery cycles work? I went on Apple's website but it remains unclear to me whether or not I should leave the computer plugged to the power socket when I'm at my desk.

    Or, should I just wait until the battery is empty and then only recharge it?

    Any help would be welcomed :)

    Thank you.

  2. macrumors demi-god


    Jul 24, 2009
    Hello Patrice.

    Some will say drain the battery and charge others will say leave it plugged in. Personally I leave my devices plugged in and take them when I go walkabout. Hasn't had any negative effects tbh.
  3. macrumors 6502


    Jun 1, 2009
    New Jersey
    I read somewhere that it is not good to let a lithium ion battery completely deplete before recharging it, with the exception of doing it once every few months for battery indicator calibration purposes.

    I'm not sure if this is what you've already viewed on Apple's website, but if not I believe the link you may have been looking for is this:
  4. macrumors regular

    Sep 17, 2008
    1) Draining the battery completely equals one full cycle of the battery. Using the battery to 90% and charging it again to 100% is a tenth of a cycle. Li-ion batteries last for a certain number of cycles, so you want to use as few cycles as you can.

    2) Keeping the battery at 100% for lengthy periods (we're talking months, not days or weeks) is bad for battery health. Conversely, using the battery on a regular basis is good for its health.

    3) Li-ion batteries nowadays do not suffer from memory issues and it is safe -- and even preferable -- to keep them topped up with small charges.

    With all that being said, the best way to keep the battery in good shape is to use it gently and somewhat frequently. Personally, I don't think it's worth wasting a cycle on "resetting" (i.e. draining 0% and charging to 100%) the battery more than once or twice a year because it's really not necessary unless there are obvious problems with the meter.

    People usually cite this when battery questions come up, but I find this a more digestible way of getting the general concepts.

    Incidentally, the consensus is that if you're not using the battery, the best way to store it is at around 50-60% charge in a cool place.
  5. macrumors 601


    Sep 19, 2008
    +1 - (this is my first post of "+1" ever)
  6. thread starter macrumors newbie

    Mar 3, 2010
    Dublin, Ireland

    Thank you very much for this very nice explanation. The Apple website is not clear at all (my view obviously).
  7. macrumors 6502

    Apr 19, 2005
    Well, the key thing is not to leave your laptop sitting at a desk plugged in 24/7/365. Other than that, just use your laptop in a normal fashion and rely on the battery technology to maximise its life.

    I use mine at uni, so pretty much fully discharge the battery everyday. In the last two years, I've done just over 650 cycles on my Rev A MacBook Air battery and still have 90% battery health (had to calibrate once when it started to fluctuate between 50% and 70%).

    Hope that helps. :)

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