Maintaining Battery Health

Discussion in 'MacBook Pro' started by Alterscape, Dec 1, 2008.

  1. Alterscape macrumors newbie

    Mar 20, 2008
    I just replaced the battery in my 15" Macbook Pro. After a bit more than a year's use, the battery's performance had degraded to the point that it wouldn't last more than 45 minutes on a full charge. My usage pattern for the battery was to leave the laptop plugged into mains power except when away from an outlet, and to recharge as soon as possible when I got back to an outlet, no matter how little of the charge I'd used -- my logic was that since Li-Ion cells have a limited number of charge cycles, I'd better charge it as rarely as possible. Obviously, this didn't work out the way I planned.

    In probably 90% of days, I'm tethered to a desk at home or at work. Some days I'll use the machine on an airplane flight, at a conference where no outlets are available, etc, but this is relatively rare.

    So I now have a Crap Battery and a Good Battery. I'm willing to switch between the two as necessary to prolong the life of the good battery. Any advice on what pattern of use will keep the good battery shiny and long-lived as long as possible?
  2. dwsolberg macrumors 6502a

    Dec 17, 2003
    Anytime I've seen anyone use a computer that's almost always plugged in, the battery tends to go out early. I use my MBP computer off battery about 25-50% of the time, although I only rarely have it go below about 30% of a charge. After a year and a half, it still lasts about 3.5 hours on a charge (I turn off Flash in my web browser, which makes a huge difference in battery life).

    If you store a battery, you should store it in a cool dry place at about 30% of capacity, and make sure it never goes completely dead. For example, never store it so long that it drops below 1% of capacity. Batteries have a limited lifetime, though. For me, it's best to just use the battery and not spend my time worrying about its life.

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