battery time keeps changing

Discussion in 'MacBook Pro' started by maccie21, May 23, 2008.

  1. maccie21 macrumors newbie

    May 21, 2008
    So I just got a refurbished macbook pro, and everything has been going great except for the battery. The first time, after I charged it up, at 99% power is 5 hrs 47 mins. Now, (after a day and a half of first opening my laptop), the time left on battery power has been fluctuating like crazy. Below is an example of the actual time vs. the battery time I recorded:

    actual time vs. battery time
    5:45 4:21
    5:46 4:00
    5:47 3:31
    5:47 3:45
    5:48 3:53
    5:49 3:55
    5:50 3:50; 3:40; 3:53 (all this changed within the minute)
    5:51 3:36
    5:52 3:33; 3:31
    5:53 3:28

    Basically, as you can see, in the first 2 minutes it went from 4:21 to 3:31, and although it goes up and down again, it never actually stayed at the 4:21 longer than a minute (or less than that). Since I got the laptop, I've installed several programs (toast, appzapper, iwork) as well as put on a best skin ever. I don't think any of these things should've made such a huge difference in battery. Oh and right now, I'm running my laptop under "normal" battery power.

    1)Is this normal?
    2)Has anyone else experienced this?

    Of course, since I just bought my laptop, the apple warranty is still there.

    3) At what point should I take it to apple, and will it matter that I have the BSE skin on it?

    Thanks all for your help :(
  2. Mashiach macrumors regular


    Mar 5, 2008
    In a House Near the Sea

    I have had several mac laptops and have this to be quite normal.
    When you are using apps on the laptop the time will go down in a predicted ratio to how long the battery would have charge if you were doing that task till the battery died. I apologize if that didn't make any sense.
    As soon as you stop doing anything the battery life will go back up.

    For example say your watching a video through vlc if you watch the battery it will fluctuate downwards till it gets to an average time. As soon as you stop the video or close the app playing the video the battery time will go back up in respect to how long the battery will last if you kept the laptop at that current work flow rate.

    So it is perfectly normal for this to happen. All you should be concerned about is how long the battery actually lasts from being charged.

    Hope this helps.

    EDIT: Also download something like istat to look at the health of your batttery this will give you more detailed information about your laptop.
  3. tdhurst macrumors 601


    Dec 27, 2003
    Phoenix, AZ

    But the overall battery life is fine? Methinks you are waaaaaay too paranoid about stuff.
  4. maccie21 thread starter macrumors newbie

    May 21, 2008
    Thanks for your help! Yea, I'm just being paranoid, but then again, since this is my FIRST mac ever (I mean 2 days ago, I had NO idea how to use anything on a mac, hardly ever touched one), so I dunno what's "normal" and what's not, since I have no reference point. Thanks again! This forum is definitely helpful :)
  5. xpovos macrumors 6502a


    Jun 7, 2007
    As stated above, the battery time indicator is predictive based on current usage, so it does fluctuate wildly. So much so that it's not at all reliable as an indicator of time remaining. A better approach is to have the batter indicator show percentage instead of time.

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