Fluctuating Battery Health

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Fluctuating Battery Health

Hi,
My battery life has been fluctuating lately. The fluctuations are very large, over the last 2 days it has gone up and down between 39% and 84%, and now it is at 58%. My battery has 283 cycles since I purchased it last september. 3 or 4 days ago I reset the smc (pmu?) and then re-calibrated the battery. I did this because my battery life was very low (39%) After that the battery health increased to 84%. Has anyone else experienced this? Any help is greatly appreciated. Thanks in advance.

Macbook Pro Core Duo, Mac OS X (10.5)

Posted on Nov 6, 2007 8:19 PM

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Answer 1

KGill Author

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Nov 6, 2007 8:52 PM in response to KGill

Those numbers are from istat, but my profiler says my batter health is fair and a full charge capacity of 3232 mAh. Is this full charge capacity low? 58% low?

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Answer 2

Nov 7, 2007 3:23 AM in response to KGill

Yes, this does occur, especially as batteries age (and 283 cycles is getting a bit long in the tooth 😉 ).

You should certianly calibrate monthly from this point forward, and plan on needing to purchase a new battery in the near future.

Having said that, you can try calling Apple or visiting an Apple Store. Apple states that a battery should maintain 80% of it's 'health' for 300 cycles. With your symptoms and number of cycles, they would probably have you do just what you did (SMC reset and a calibration) and respond that that brought you above 80% so your battery is within spec. But there are known issues with the MBP batteries, and they did extend the battery warranty to two years for all Core Duo machines (link below for details). You may be able to get a replacement battery free of charge.

http://www.apple.com/support/macbook_macbookpro/batteryupdate/

Hope this helps...

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