MBA Owners! Calibrating my battery improves accuracy of charge capacity reading 100%!

Discussion in 'MacBook Air' started by Jobsian, Jun 21, 2012.

  1. Jobsian macrumors 6502a


    Jul 30, 2009
    That's "to 100%" but not enough room. In this thread where we were plotting our battery's full charge capacities I noticed than mine and a few other people's was lower than the design capacity (4600 mAH on 11" Air). I initially got 4592 then a bit lower and fellow poster GGJstudios kindly gave us some info on normal fluctuations and a link for Batter FAQs.

    Now it says in the FAQs that non-replaceable batteries on new Apple notebooks are already pre-calibrated but it "won't harm your battery" to calibrated it to make the readings more accurate and boy does it work! On another battery health thread someone suggested (paraphrasing) that you'd be lucky to get the exact design capacity.

    After zeroing the battery until the computer switched off and leaving it out of power overnight, charging it back to full this morning (standard calibration), I see this, bang on the design capacity spec:

    Full Charge Capacity (mAh): 4600

    Health also went up to 98% (on iStat).

    Anyone else getting improved readings after calibration?
  2. GGJstudios macrumors Westmere


    May 16, 2008
    It just as easily could have come back with 96%, vs 100%. Calibration will not always give you a higher number. In most cases, the number will be lower. Again, the built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries. Battery readings are only estimates. They are not exact, even with calibration. Calibrating your battery is putting another cycle on your battery needlessly. Just use your Mac and don't obsess about trying to get precise battery readings, because it won't happen.

    This should answer most, if not all, of your battery questions:

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