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zentenk

macrumors member
Original poster
Apr 17, 2010
39
1
I noticed that the full charge capacity for my mac varies. On first charge it indicated 6580mAh, then on second charge 6685mAh(which the software indicated that I was able to fully charge to this capacity), then now after I unplugged it for a bit it now says the full charge capacity is 6850mAh. I'm planning to calibrate my battery on this discharge.

Anyone experience this?
 
My indicated battery capacity (15" i7) has been slowly increasing this week. Started at 69xx and it now about 7150 mAh. Nameplate capacity on the battery is listed as 7700 mAh, be interesting to see how far in this actually goes.

The battery chemistry is A123 Li-polymer. These are very picky batteries, and the cells can be ruined if they discharge below about 3.1V/cell, or if the cells get unbalanced. I would guess the battery controller is conservative, and this explains the difference between the nameplate and measured capacities. Simply the controller being careful to keep each cell above the threshold voltage.
 
on the note of battery calibration should i let it increase more before I do the calibration for more accurate battery estimates?
 
What's the best way to go about calibrating the battery in our new MBPs? Coconut battery program? What's the process to discharge/charge/calibrate that is suggested?
 
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