3 Replies Latest reply: Jun 16, 2009 2:01 PM by Network 23
emhak Level 1 Level 1 (0 points)
Hi,

I got a couple of questions concerning the Mid 2009 macbook pros.

I recently got one of them and followed the calibration steps as stated by Apple except that I didn't let the Macbook rest 1 night before recharging it. So is it possible to re-calibrate the battery again or am I stuck?

Second my macbook now shows me weird battery timing. At all times my backlight is off, bluetooth off and i'm just running Safari 4. The first time I get 2:00 battery life but after I restarted my macbook pro, it jumped up to 7:00 hrs battery life and then fluctuated between 5-7 hours. Is that normal?

Thanks.

Mac OS X (10.5.7)
  • Network 23 Level 6 Level 6 (11,870 points)
    You can probably recalibrate whenever you want. But avoid doing it more than once a month, usually.

    The time remaining is just an estimate, taking into account what you are doing right now. If you are doing things that demand a lot of power, the estimate must fall, because if you keep draining power that much the battery can't last as long. If you are doing things that use less power, the estimate will rise. If you switch from word processing to video editing and then stop video editing to read email for 10 minutes, the time estimate will go way down, then way up.
  • emhak Level 1 Level 1 (0 points)
    oic. What about the percentage? Is it the same as the Time Remaining in providing a rough estimate? I'm just bugged by it because of the advertisment of it being able to hold 7 hours and I'm managing 3-5 hours just surfing the net.
  • Network 23 Level 6 Level 6 (11,870 points)
    emhak wrote:
    oic. What about the percentage? Is it the same as the Time Remaining in providing a rough estimate? I'm just bugged by it because of the advertisment of it being able to hold 7 hours and I'm managing 3-5 hours just surfing the net.


    Percentage should be more "accurate" since it should be a real number, unlike the Time Remaining estimate.

    CPU demand can have a large effect on battery life. While web surfing should not use much CPU, one type of Web surfing does: Flash. If you surf sites using a lot of Flash, or leave Flash animations running in browser tabs or windows left open in the background, the CPU usage of Flash will empty your battery. That is just an example of how an unexpected factor affects battery life. If you are constantly getting lower battery than rated, I would check Activity Monitor and see which apps are working the CPU too hard.

    Check these two reviews. They get eight hours out of the battery, and they use their own non-Apple tests.
    Anandtech review
    Laptopmag review