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*Post your 2012 MBA's battery Full Charge Capacity (mAh)*

Jobsian

Jobsian

macrumors 6502a
Original poster
Jul 30, 2009
853
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I'm wondering about the variability here as it seems quite high from what I'm reading. From this site it seems the design capacity of these batteries is

4680 mAh for the 11" models
and
6700 mAh for the 13" models


Post which 2012 MBA you have and its capacity from the System Report (click About This Mac in the top left of the screen then 'more info'). Mine:

11" - Full Charge Capacity (mAh): 4592


_
 
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Does anyone know whether or not this is a fixed number early on into the cycles, as we're already seeing some variability?
 
The full charge capacity will go up and down throughout the machine's life. This is normal. It can range from 85% to 110% and still be normal.
 
My 11" has fluctuated a bit from 4732-4799 (currently 4786 on 3 cycles). Haven't bothered to do a full calibration yet, just got the machine yesterday. Will let it go thru a few more cycles first.
 
2012 11" base Air
5 charge cycles
Full Charge Capacity (mAh): 4516

That kinds sucks, right?
 
Beau10 said:
Haven't bothered to do a full calibration yet, just got the machine yesterday. Will let it go thru a few more cycles first.
Click to expand...
The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.

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

jgc said:
First Mac here...how do I check?

Cheers.
Click to expand...
iStat Pro will give you battery information, as well as temperatures, fan speeds, uptime, etc. It's very handy.... and free!
 
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jgc said:
First Mac here...how do I check?

Cheers.
Click to expand...

From the "About This Mac" window click "More Info...". Then click "System Report..." and "Full Charge Capacity (mAh)" is listed under "Power".

My 13" currently lists 6566.
 
GGJstudios said:
The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.

This should answer most, if not all, of your battery questions:
Click to expand...

While the battery may be now calibrated from the factory (and that's interesting, thank you), that they do not benefit from further calibration is certainly wrong - they must be speaking to a consumerist POV where sure, it isn't quite necessary "do not require". I experienced this in my last MBA and would routinely see my battery change by up to 5% after letting it go for a couple months.

All lithium ion batteries suffer drift in their readings, and clearly that's what I was getting at - getting an accurate reading of the capacity. That's the point of this thread, no?
 
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Beau10 said:
While the battery may be now calibrated from the factory (and that's interesting, thank you), that they do not benefit from further calibration is certainly wrong .
Click to expand...
Tell that to Apple. Generic information about lithium ion batteries don't necessarily apply to the specific implementation in Apple's lithium polymer battery technology. I would trust the manufacturer, who is financially responsible to replace defective batteries and who is responsible if the information they provide is flawed. They know more about their own technology than any generic site.

While calibrating the battery in unibodies won't harm it, it's not necessary.
 
GGJstudios said:
Tell that to Apple. Generic information about lithium ion batteries don't necessarily apply to the specific implementation in Apple's lithium polymer battery technology. I would trust the manufacturer, who is financially responsible to replace defective batteries and who is responsible if the information they provide is flawed. They know more about their own technology than any generic site.
Click to expand...

Tell what to Apple? The point of this thread and "replacing defective batteries" are orthogonal to each other.

Apple may have somehow reduced the tendency to drift, but there's no way they can fix what is inherent in the technology.
 
I'm 4 cycles in and from my opening post when I was getting 4592 mAh, it has gone down to

Full Charge Capacity (mAh): 4576

I wonder if this is normal? Will be interesting to see where it goes from here, I'm hoping up!
 
Jobsian said:
I wonder if this is normal? Will be interesting to see where it goes from here, I'm hoping up!
Click to expand...
It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

This should answer most, if not all, of your battery questions:
 
GGJstudios said:
It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

This should answer most, if not all, of your battery questions:
Click to expand...
Thanks, will do.

Health at 97%
 
Did a recalibration. Guess what I got?

11" Full Charge Capacity (mAh): 4600

Right on the money!
 
On my 11" I am getting:
Full Charge Capacity (mAh): 4454

Which I think is the lowest so far. I might try the calibration thing, though supposedly you don't need too.
 
Hichisky said:
On my 11" I am getting:
Full Charge Capacity (mAh): 4454

Which I think is the lowest so far. I might try the calibration thing, though supposedly you don't need too.
Click to expand...
You definitely don't need to calibrate. Remember, calibration does not affect or change your battery health in any way. It only makes your readings more accurate.
 
GGJstudios said:
You definitely don't need to calibrate. Remember, calibration does not affect or change your battery health in any way. It only makes your readings more accurate.
Click to expand...

Yeah, I know, I was speaking in terms of getting a more accurate reading. But I figure I won't bother. I feel the battery life is pretty decent anyway. Thanks. :)
 
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