Macbook Pro Battery question

Discussion in 'MacBook Pro' started by poblack, Feb 28, 2010.

  1. poblack macrumors regular

    Joined:
    Jul 11, 2007
    #1
    I just purchased a refurb. 15.4 2.53 MBP with the 7 hour battery. I notice that when the battery is fully charged it will sometimes say 7 hours left, but most of the times it says 4.5 hours or something like that after I charge it. Is something wrong?
     
  2. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #2
    No- the "time remaining" is calculated at verious intervals and is based off of how much power your machine is using at that time. So if it's calculated when you're ripping a CD or encoding something it'll be less than if it's calculated just sitting idle.
     
  3. arogge macrumors 65816

    arogge

    Joined:
    Feb 15, 2002
    Location:
    Tatooine
    #3
    Those battery-life claims from Apple should be based on when the computer is actually doing work, not when it is sitting idle. If it only lasts 4 hours under load, that's what the claim should say. It's like if a car company says this or that car gets some unbelievable mpg rating, but they don't tell you that this only applies when you're driving on a flat surface or down a hill, and don't exceed idle engine speeds.

    I'm wondering what I should do when my 7-hour battery doesn't last as long as expected, and I need the computer to keep working but I can't plug it into a wall socket. How do you deal with the problem of not being able to hot-swap the battery?
     
  4. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #4
    It really shouldn't. Everyone's "usage" is different.

    All car advertisements with a mpg rating have the disclaimer along the lines of "Actual mileage may vary."
     
  5. arogge macrumors 65816

    arogge

    Joined:
    Feb 15, 2002
    Location:
    Tatooine
    #5

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