MBP 13'' i5: Battery problem? 79% = 3h 2 mins only?

Discussion in 'MacBook Pro' started by radicaldog, Mar 20, 2011.

  1. radicaldog macrumors member

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    Mar 1, 2010
    #1
    My MBP is brand new. Tonight was the first time that I used it on battery. I just did some light browsing (no Flash or video) and word processing for a couple of hours. And now it's telling me that it has 79% of the battery charge left, and only 3 hours and 2 mins. Is that normal? Wasn't the battery supposed to last 8 hrs or so? iStat Pro says the battery is at 99% health. Also, the estimated remaining time keeps changing, though not by much. I'm worried.
     
  2. 87am macrumors regular

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    Feb 27, 2011
    #2
    What level brightness are you using? Backlight keyboard up all the way?
     
  3. radicaldog thread starter macrumors member

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    #3
    Brightness is six notches. The backlit keyboard is on whatever setting it came with (I migrated from my old MB, which didn't have a backlit keyboard).
     
  4. alust2013 macrumors 601

    alust2013

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    #4
    It will fluctuate. That's just an estimation of how long it will last given the load, charge, etc. when it is calculated. It should refresh every few minutes, and it's not necessarily accurate.
     
  5. radicaldog thread starter macrumors member

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    #5
    Fair enough, but shouldn't it be a lot more anyway? I mean, 80% and only 3hrs? How's that possible if the battery is supposed to last 8hrs or more?
     
  6. alust2013 macrumors 601

    alust2013

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    #6
    There may be some flash hidden in some pages you are viewing, etc. You can check out activity monitor and sort processes by CPU usage to see if something is using a large amount of power. The battery is rated at 7 hours, and 80% of that is about 5:30, so I'm guessing you have a background process using CPU or something in a webpage.
     
  7. radicaldog thread starter macrumors member

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    #7
    CPU usage: around 27% user, 7% system. No idea if that's normal. I'm talking on facetime at the moment though.
     
  8. alust2013 macrumors 601

    alust2013

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    #8
    There's your battery hog. 27% CPU will use battery a lot faster than just web/word, which is usually 10% or less. I'd say that estimation is reasonable. That's perfectly normal for Facetime though.
     
  9. Mik3F macrumors 6502

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    #9
    That there is the reason
     
  10. radicaldog thread starter macrumors member

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    #10
    Yeah but it was already too low. In fact now it's gone to 1h 25min (i.e. it lost 1.5 hrs of charge) in 15 mins of facetime or so.
     
  11. Mik3F macrumors 6502

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    #11
    facetime is a cpu hog. The more cpu you use the faster the battery will deplete
     
  12. radicaldog thread starter macrumors member

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    #12
    OK, but my worry was that it was at 80% and 3hrs before using facetime. Is that normal?
     
  13. Mik3F macrumors 6502

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    Feb 3, 2011
    #13
    All depends on what you were doing, settings etc.

    Turn the brightness down, keyboard backlight off etc will prolong the battery life
     
  14. radicaldog thread starter macrumors member

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    #14
    OK. I was just doing light browsing and word processing. It doesn't sound right to me.
     
  15. alust2013 macrumors 601

    alust2013

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    #15
    Just let it cycle through a few times, it should get closer to 7 hours. I wouldn't expect quite 7 hours though, it's almost never as long as advertised, for example, my computer has a "5 hour" battery that lasts 3.5-4 hours with very light use.
     
  16. erphan, Mar 20, 2011
    Last edited: Mar 20, 2011

    erphan macrumors newbie

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    Jan 6, 2011
    #16
    It's really just an estimation.

    My 15" i7 Quad gives me like 5 hours on Firefox and Word with Outlook constantly fetching emails every minute. This is what I have right now:

    [​IMG]

    But with my CPU usage bordering 2% I still only get between 4-5 hours, event though this is estimating 6 more hours. It's gonna fluctuate a lot for the first few weeks but eventually the computer will figure out what the actual battery life is.
     
  17. radicaldog thread starter macrumors member

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    Mar 1, 2010
    #17
    Thanks, guys. I've got FaceTab and GmailTab running and fetching material every minute, so that might explain some of the battery drain.
     
  18. gorskiegangsta macrumors 65816

    gorskiegangsta

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    #18
    That's because the system keeps re-estimating the remaining charge based on your current usage. Thus, it is not uncommon for battery indicator to jump up or down a few hrs.
     
  19. solaris7 macrumors regular

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    Feb 17, 2008
    #19
    Haha. Sorry but a 15" i7 quad CPU's usage at nearly 0% made me chuckle :)
     
  20. ender land macrumors 6502a

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  21. GGJstudios macrumors Westmere

    GGJstudios

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    #21

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