Does constantly running on AC Power wreck the battery?

Discussion in 'MacBook Pro' started by Mew2468, Sep 1, 2009.

  1. Mew2468 macrumors regular

    Joined:
    Apr 11, 2009
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    Home of the 2010 Winter Games
    #1
    When I wake up, I power up my MacBook Pro and plug in the AC adapter. I turn it off and unplug it when I go to school. When I get back home, I turn it back on and run it on AC power until I go to sleep.

    Is this bad for the battery? I know I should cycle it every couple of weeks, but is running it on AC power for a majority of the time bad for my MacBook Pro?
     
  2. MadGoat macrumors 65816

    MadGoat

    Joined:
    Jul 30, 2007
    Location:
    Canada
    #2
    So will say yes, I will however say no.

    I have always run on AC for 80-90% of the time and I have never noticed any shortening in life span for my battery beyond normal wear and tear.

    (don't re calibrate more than once a month, if that)
     
  3. Mew2468 thread starter macrumors regular

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    Apr 11, 2009
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    #3
    Okay, I'll run it on AC when possible. Thanks for the reply :)!
     
  4. vant macrumors 65816

    Joined:
    Jul 1, 2009
    #4
    No.

    Some laptops are designed specifically to be run through AC (Alienware) and they have no battery issues.
     
  5. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #5
    You'll actually "wreck" your battery if you decide to keep draining/charging. Current battery technology is such, that you get only a certain number of recharge cycles before you start seeing a drop off in battery performance. Deep draining is particularly bad but constant use will bring the battery closer to the point where its not hold as much of a charge anymore.

    I keep my MBP plugged in all the time (when not traveling) and have not noticed any issues, in fact I've done that with all my Mac laptops and never once has the battery died before its time.
     
  6. Vster macrumors 6502

    Joined:
    Jan 19, 2005
    Location:
    Celina, TX
    #6
    Nope, it should make the battery last longer. Just calibrate every now and then as the other member posted.
     
  7. Mew2468 thread starter macrumors regular

    Joined:
    Apr 11, 2009
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    Home of the 2010 Winter Games
    #7
    So how often do you recommend cycling the battery? Some sources say every week, some say every 2 weeks, and some say every month.
     
  8. m85476585 macrumors 65816

    Joined:
    Feb 26, 2008
    #9
    I would say constantly running on AC will eventually wreck the battery. Doing that keeps it at 95-100% charge all the time, which will cause it to lose capacity over time. If you buy a new battery you will notice that it comes around 40-60% charged because that is optimal for maximizing battery health.

    Personally, I try to put on at least a cycle a week if I am otherwise only using AC. At that rate, it will still be 6 years before the battery reaches 300 cycles if you have an older MBP or 20 years before you reach 1000 cycles if you have a newer MBP.

     

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