New MBP remaining battery very "jumpy"?

Discussion in 'MacBook Pro' started by foxpat, Apr 20, 2010.

  1. foxpat macrumors newbie

    Joined:
    Jan 16, 2010
    #1
    Hey all
    I've just gotten my new MBP 13-inch with the 10-hour battery, but the remaining battery viewer is being very weird...
    Just by surfing the web (with one tab) and doing nothing else with screen at 50% and backlit keyboard at 2 notches, the remaining battery has displayed times ranging from 4 hours 50 minutes left to 11 hours 15 minutes left..
    The percentage of battery left is 96%, btw

    Is this normal?

    Thank you very much.

    Running Geekbench and two windows open gives 5 hour 39 minutes
     
  2. macsr1 macrumors member

    Joined:
    Apr 3, 2010
    #2
    Happened to me too.

    But right now I've been running since 7:00 (now its 10:43) and it still says I have 2:34 left (37%).

    So if it holds up, it will have run for over 6 hours. Pretty good.
     
  3. foxpat thread starter macrumors newbie

    Joined:
    Jan 16, 2010
    #3
    hmm, well I've just been watching a youtube video at 720p, and it just displayed 3:34, which is pretty bad :(
     
  4. Mark Booth macrumors 65816

    Mark Booth

    Joined:
    Jan 16, 2008
    #4
    The battery time remaining indicator bases its estimate on the process you are running at any given time. If you are playing a movie from DVD, it's going to assume you'll be doing that until the battery is exhausted so it bases the time estimate on the large power drain of playing a DVD. If you are listening to music with the screen asleep, it will base it on that and show much longer battery life. If you are browsing the web and you spend time on pages with Flash, it will assume a bigger battery drain because pages with Flash use more power than those without.

    I believe the battery remaining indicator gets better at predicting a realistic time as that particular charge gets used up. It starts "averaging" the use over the previous hours and gets more accurate. But dramatic changes in power use will, again, throw it for a loop.

    Mark
     
  5. Pivot macrumors newbie

    Joined:
    Apr 13, 2010
    #5
    I've noticed that it seems to jump a lot even between menial tasks. For example, just switching between pages and numbers sometimes causes it to go down sharply, followed by a gradual climb back to equilibrium.
     

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