New uMBP 15" Battery Health/Capacity

Discussion in 'MacBook Pro' started by mgnayim, Mar 12, 2010.

  1. mgnayim macrumors newbie

    Aug 14, 2009
    I bought my first mac one month ago, its a new uMBP 15".
    CoconutBattery and iStat Pro weer installed in the first day, to keep an eye on the battery health.

    I noticed that the original (after 1 cycel) battery capacity was around 6900 mAh, 400 mAh more than Apple's standart to this model(6500 mAh).

    But the thing that diving me mad is the rate of the capacity drop!

    Every one cycle the capacity drops in aprox. 50-100 mAh [it was ~50 mAh in the frist 10 cycles, and now its ~100 mAh per cycle]

    The battery now is on 19 cycles and 6300 mAh- 97% of 6500, but actually its 92% of 6900.

    Apple claims that the newer battery can hold 80% of its capacity after 1000 cycles. but if my battery keep it this way... it will reach the 80% on 50 cycles.

    Is that normal? Should I worry about it?
  2. Pax macrumors 6502a

    Dec 12, 2003
    Don't panic.

    The capacity is just a guess, the computer doesn't really know it very accurately. It's just like the gas gauge in your car - not very precise. It will change each time you charge, sometimes up and sometimes down. That's probably why Apple sets the 80% threshold:- the capacity will normally change from about 90 - 100% from charge to charge.

    The 6500 mAh capacity is just a nominal value, some will be higher and some lower than this. You can't be complaining that you've got 6900 mAh?!

    Even if you calibrate your battery, then calibrate it again, you will get a different answer, depending upon the circumstances (ambient temperature, last usage pattern etc) of the battery.

    Don't worry about it, all perfectly normal.
  3. wschutz macrumors 6502

    Jun 5, 2007
    Keep using it in the mean time...

    When you get 80% and less than 100 cycles, call them and ask for a replacement. It will still be under warranty, so no charge for you.

    I don't think that at this point you can really prove that it's faulty, you can try though. But unless it doesn't let you sleep or stresses you much... I wouldn't worry, because you still have time to test it.

    Don't forget to calibrate it, just in case ;)
  4. nigameash macrumors 6502

    Dec 6, 2008
    Space: The Final Frontier
  5. rk505 macrumors newbie

    Jan 27, 2010
    i had similar fears, as my battery capacity had fallen to 92% after just 3 cycles, I had calibrated my battery etc. as apple recommends. I took my uMBP to the apple store and I was told that the gauge is notoriously inaccurate on new MBs when they are being first used. It looks as if they were right, and my capacity has been increasing ever since and is now at 98% on 52 cycles. Like one of the previous posters said, hang back a bit and wait to see if it falls to 80% any time soon. Then I would imagine you will have no problem getting a new battery.
  6. mgnayim thread starter macrumors newbie

    Aug 14, 2009

Share This Page