7 Replies Latest reply: Feb 23, 2010 1:30 AM by Rod Hagen
iheartbangs Level 1 Level 1 (0 points)
i bought my macbook pro 3 months ago and then i upgraded to snow leopard, everything was fine.

previous to my macbook i had an HP laptop and the battery lasted 15 minutes.. so to learn more about my battery
i downloaded istat, and coconut battery since i heard about them being pretty good.
i wanted to maintain my battery to be its best.

i enjoyed a couple of weeks with 100% battery health according to coconut battery, but istat was always 1 percent below what coconut battery said.

so coconut battery = 100%, istat = 99%

every month i calibrate my battery: i charge it fully then leave it plugged in and charge for two hours then unplug and use it until it runs out, then let it rest for 5 hours or more then charge it all the way again.

for the past week or couple of weeks i noticed my battery slip from 100 to 99%
this got me upset (since im a stickler with my electronics) so i calibrated and it didn't go back to 100, which i thought was going to happen after i calibrated it again.
a week later i turn on my macbook and its now at 97% now im getting freaked out.

i don't know what im doing wrong.. usually i plug it in then unplug it after its full then charge it again to 100 then unplug it then go to sleep. but after that drop to 98 percent i started to just keep it plugged in thinking it would be better for the battery.. but now its 97 percent.. so i don't know what to do..

if i calibrate it again would it go back to 100 percent health?
is it normal for a 3 month old macbook to be at 97 percent already?
i have 84 charge cycles if this info will help.

please give me feedback! i want to bring it back to 100 if possible and i wanna if the problem is w/ my battery

macbook pro 13 inch, Mac OS X (10.6.2)
  • Kappy Level 10 Level 10 (260,260 points)
    You're doing nothing wrong. A battery's "health" of maximum charge capacity declines with use. You should not recalibrate your battery as often as you do unless you never use the computer on battery power. If the battery is used and being heavily discharged within a one or two month period then there's no need to calibrate.

    The purpose of calibration is to keep the measurement of the declining charge while in use closely tied to the battery's actual charge reduction. Calibration will not make your battery any better or last longer.

    As for the battery indicator in your menubar, it tells you how much usage time is left or if the battery is charged. Sometimes it shows the battery is fully charged at 100% and sometimes it may indicate a slightly lower percentage even though the charger has turned green. This is normal.
  • tavella Level 1 Level 1 (0 points)
    I hope someone may be able to assist me with my question. Just like the original poster, my MBP went from showing 100% to only showing 95% and my MBP is less than a month old. Is there a possibility that I may have a defective battery? My laptop is seldom unplugged and when I do, I let the battery fully discharge before plugging it back in.

    Thank you.
  • eww Level 9 Level 9 (52,975 points)
    tavella: For the longest possible battery lifespan, don't completely discharge your battery each time you use it, but do run on battery power often enough to cycle the battery once or twice a week. What you are doing now, as you've described it, is a recipe for shortening the lifespan of your battery. Deep discharges are hard on it, as are long periods without any "exercise" at all. Frequent partial discharging followed by recharging to full capacity is much more to the battery's liking.

    Your battery's "health" readout will vary up and down from time to time by as much as five percentage points each way. It just isn't any more accurate than that. Don't obsess over it. Check it again in six months, not six hours or six days. If it's significantly below 90% then, you probably did get a bad battery, and Apple will most likely be glad to replace it under warranty, as they have for other users whose batteries have aged or failed prematurely.

    Read this carefully:


    Message was edited by: eww
  • OVNIto Level 1 Level 1 (0 points)
    Hey guys!!!

    I have a Macbook Pro 13, bought in October 2009 and i'm worried about the battery Health. After 41 cycles it is showing 89% of Battery Health and even after calibrate it, it just go to 91/92% in maximum.

    I was having problems with my trackpad, so i went to a authorized Apple maintenance here in Brazil and they said to me that their program (the one which analyze the battery) is showing that the Battery is ok, even the Health arounds 90% and they said that they cannot call the warranty because of that.

    But for a 2 months Macbook Pro 13' it is too much lost isn't it? What do you guys think about? Should i worried or should i stay calm?

    Thank soo much by your support.

  • Glenn Carter Level 4 Level 4 (3,360 points)
    Stop worrying about it! If it eventually goes bad within the first year Apple is going to replace it anyways. And if you have Apple Care, then the battery is covered for the life of the Care. I have had 3 batteries replaced for free and 2 of them were from the same MacBook.

    Review this page on Apple's site:


    As long as you drain it and recharge at least once a month, the health will be good. Cheers!
  • jcbecker Level 1 Level 1 (0 points)
    I've got a late 2009 MBP 13. The battery only has 51 cycles on it and the health is down to 90%. I've tried the calibration procedure, but it only seems to make the battery WORSE. Battery life is o.k. at best (given the claims about it). I was getting 4-5 hours now it's only 3. At this rate the battery won't last another 6 months...
  • Rod Hagen Level 7 Level 7 (31,985 points)
    Maybe you simply have a bad battery, jc? Take it to an Apple dealer and get it stress tested. Hey, you are obviously still way, way, way within the warranty period!