Full charge capacity seems low after initial calibration

Question

Level 1

31 points

Full charge capacity seems low after initial calibration

So even though there's no mention of a need to calibrate the MBA, I decided that it couldn't hurt and I calibrated my new MacBook Air right away per Apple's instructions on their website for the Macbook/Macbook Pro line: fully charged it when I initially plugged it in, after reaching full charge, let it stay charging for at least two full hours, then unplugged and let it discharge and go to sleep and left it sleeping for five hours (well, actually it may have been closer to 4-4.5 hours-it was in deep sleep mode when I woke it and plugged it back in) and then I fully recharged. Now it's saying that my full charge battery capacity is 4899 mAh whereas the original battery capacity was 5200 mAh...why would it have dropped so low after calibrating?

24" iMac 2.8 Ghz Intel CD2 Extreme/MacBook Air on order, Mac OS X (10.4.3)

Posted on Feb 7, 2008 9:07 AM

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Answer 1

Susan Dennis Author

Level 1

31 points

Feb 11, 2008 6:49 AM in response to Susan Dennis

Well, after calibrating again, mine seems to have settled at 4865 (93%) of original capacity...at least for now. This last time I let it sleep for a good 6 hours and made note that the computer had actually completely shut down (no sleep light). I'm hoping that with use, it will creep back up a little. So far it's been at 95% (very briefly after first calibration) 92%, and currently 93%. I do recall my MacBook Pro fluctuating here and again with the percentages.

Thanks for everyone's input so far and reassurances...I just wanted to make sure this was "normal" and not an indication of a bad battery. So far, I've gotten very good battery life-in the 4 hour or more range with just the usual surfing, email, etc.

Love the MacBook Air so far!

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Answer 2

Feb 7, 2008 9:26 AM in response to Susan Dennis

I am on my second air. I have done the same thing and am having all kinds of bad results. Last night after 8 hours my batt was only at 76% I am going to the apple store and demand a refund with no restocking fee. There is a serious problems with these batteries or charging circuitry. After all these batteries will only get worse over time. I am a desktop support tech/network engineer and have dealt with many pc/mac laptops and have never seen anyhting like this. I did the calibration on both.

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Answer 3

Susan Dennis Author

Level 1

31 points

Feb 7, 2008 9:52 AM in response to Richard Spangler

I'm not really having any problems...I mean, my battery is fully charging to 100% and in a nominal length of time. Sounds like your experiencing a different issue-which I can totally empathize and hope you get it resolved soon. For what it's worth, I've always had very good experiences with Apple support.

I'd just like to know if it's normal for the total capacity to have dropped so soon & after just one calibration...?

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Answer 4

Feb 10, 2008 9:01 PM in response to Susan Dennis

I am not sure this actually a problem. With a lot of different portable Apple computers I have seen the original capacity change after the calibration. I think the original number may be "preset." The drop in numbers probably doesn't actually reflect a drop, rather an accurate reflection.

Also I have noticed that after a few use cycles a calibration will usually result in a slightly higher capacity.

FYI mine dropped to 4918 after first calibration.

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Answer 5

Feb 11, 2008 3:20 AM in response to Susan Dennis

The initial value is a preset value which, if all cells were operation at theoretically 100% in a perfect world then that would be the value. Now you will never get that value instead you get what your real world battery has once its settled. 4900 is a good value and most new batteries would settle around that mark. That 94% of theoretical best, not too bad and it will most probably stay around that value for a good while.

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Answer 6

pey000

Level 1

0 points

Feb 15, 2008 12:26 AM in response to Susan Dennis

I'm having major problems with my battery. The charging light will go to green after about 30 minutes, but there is little charge in the battery...battery indicator is frequently telling me I have 20 minutes left of life.

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Answer 7

Rhyd

Level 3

806 points

Feb 15, 2008 10:25 AM in response to pey000

Open the System Profiler (either directly or through About this mac > more info > hardware > power > battery information > charge information and > health information. What info do you see there?

Also: do the battery calibration; it helps the computer correlate the actual battery to the actual computer.

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Answer 8

Mar 9, 2008 3:35 PM in response to Rhyd

I'm having quite a low capacity reading (4104) after the first full discharge and charge cycle...hope it improves...

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Answer 9

iMacoo7

Level 1

27 points

Mar 10, 2008 6:57 AM in response to Rhyd

IF my cycles states:6
And my health is :97% (4982mAh)
And its fully charged and plugged in.Is that good?

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Answer 10

Mar 10, 2008 8:21 AM in response to iMacoo7

Hi,

close to perfect!

Volker

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