Battery Life of MacBook Batteries

Discussion in 'Mac Basics and Help' started by ericmjl, Aug 13, 2007.

  1. ericmjl macrumors member

    Jul 3, 2006
    Hey guys,

    I just have a question. I've had my MacBook for about a year now, and I've noticed a considerable drop in battery performance over the year.

    Hence, I checked the system profiler to get an idea of how many mAh my battery can last, and at the time of writing, its full charge capacity is 1918 mAh. How long is your battery capacity rated at? Is it over 2000mAh, if it's new? Or is it less than 2000 mAh, if it's getting a bit older?
  2. kikobarbada macrumors regular

    Jun 28, 2007
    The default is 5200, so your battery is screwed.
  3. maestrokev macrumors 6502a


    Apr 23, 2007
  4. ericmjl thread starter macrumors member

    Jul 3, 2006

    Yes, I've used that utility to try to see my cycle count and stuff. However, the Apple technician at UBC was very good about replacing the battery for free, and he did that within one day.

    Macs and Mac people are just awesome. ;-)
  5. BioChron macrumors regular


    Jun 13, 2006
    Be sure to cycle through the battery, rather then start charing when the battery is half full or something.

    - Daniel
  6. GreatDrok macrumors 6502a


    May 1, 2006
    New Zealand
    This is bad advice. It was true in the days of NiCad batteries but modern batteries do not need to be discharged all the way. Just use you machine and plug it in when a power supply is available. The battery should be good for about 300 cycles on average and a cycle will be a full discharge. Partial discharges will be summed so three charges of 1/3rd will be a full cycle. Li-ion batteries don't suffer from the memory effects of NiCads so they don't need full discharge/recharge cycles.

    FYI, I'm on my third battery for my MBP. The first was replaced because it was a fire hazard so was recalled. The replacement was OK for a while but then suffered a rapid loss of capacity as many others have. After only 58 cycles it was down to less than half its original capacity. I'm now on my third which seems OK for the moment. Most of the time I keep the machine on mains power to reduce the number of recharge cycles.
  7. sbluetruck macrumors regular


    Jul 25, 2007
    Wisconsin der hey
    be sure to calibrate you battery every MONTH or so.
    most people don't do this and it's important that you do it, so you can keep your battery for as long as possible.

    from Apple:
    "PowerBook G4 (15-inch Double-Layer SD), MacBook (all models), MacBook Pro (all models), and MacBook Pro (17-inch) (all models)
    The battery calibration for the PowerBook G4 (15-inch Double-Layer SD) and any model of MacBook or MacBook Pro has been updated because of a new battery released with this computer. With these computers, follow these steps to calibrate your battery:

    1) Plug in the power adapter and fully charge your PowerBook's battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.

    2) Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.

    3) Disconnect the power adapter with the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, you will see the low battery warning dialog on the screen.

    4) Continue to keep your computer on until it goes to sleep. Save all your work and close all applications when the battery gets very low, before the computer goes to sleep.

    5) Turn off the computer or allow it to sleep for five hours or more.

    6) Connect the power adapter and leave it connected until the battery is fully charged again.

    Tip: When the battery reaches "empty", the computer is forced into sleep mode. The battery actually keeps back a reserve beyond "empty", to maintain the computer in sleep for a period of time. Once the battery is truly exhausted, the computer is forced to shut down. At this point, with the safe sleep function introduced in the PowerBook G4 (15-inch Double-Layer SD) computers, the computer's memory contents have been saved to the hard drive. When power is restored, the computer returns itself to its pre-sleep state using the safe sleep image on the hard drive."
  8. anson89 macrumors newbie

    Aug 19, 2007
    I'm just wondering
    Most of the time my Macbook stays at home
    So should I leave my battery on the Macbook or just take it off while my AC is plugged in? And just use the battery when I'm on the run

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