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SenorVvangIstMoi

macrumors member
Original poster
Oct 24, 2011
78
4
Bristol, UK
Hey guys.

I've been using my new Air for a couple of days now and really fallen in love with this beauty. However I realized that the brand new MBA is not shipped with a battery capacity of 100%. I started to worried about it.

I ran both coconut battery and Battery health since the first boot. The original battery capacity stated on both program are 6700mAh, but my 2day's old MBA currently only has 6598mAh, which is a 2% dropped.. what should I do to prevent this from occurring? Or is it true that every new Macbook computer does not guarantee a full 100% flawless battery?

Can any apple genius explain this to me please.. I couldn't find any credible result from Google.. Your comments are appreciated.

Thanks guys!
 

jimboutilier

macrumors 6502a
Nov 10, 2008
647
42
Denver
My 2010 11" MBA showed 97% when I first got it and I had the same worry. After a few full discharge cycles it went to 98%. It's stayed at 98% for the last two years.

My new 2012 MBA reads 98% without any discharge cycles. 100% would have been nice but I'm not too worried after my experience with my 2010 model.

Who knows how accurate the numbers are. All I can say is I get good battery life and that remained true on my last MBA for over two years.
 
Comment

SenorVvangIstMoi

macrumors member
Original poster
Oct 24, 2011
78
4
Bristol, UK
Don't worry at all by this, it's an inaccuraute recording, check out this thread including my own fluctuations:

https://forums.macrumors.com/threads/1390507/

Thanks for your the link and your confirmation!

----------

My 2010 11" MBA showed 97% when I first got it and I had the same worry. After a few full discharge cycles it went to 98%. It's stayed at 98% for the last two years.

My new 2012 MBA reads 98% without any discharge cycles. 100% would have been nice but I'm not too worried after my experience with my 2010 model.

Who knows how accurate the numbers are. All I can say is I get good battery life and that remained true on my last MBA for over two years.

Yup. I agreed with you. There can't be a perfect battery test app out there. And the mid-2012 MBA's battery is truly amazing for its usage under normal stuff such as 8 hours of battery life on low brightness.
 
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tim100

macrumors 65816
May 25, 2009
1,368
0
my macbook air started out at 95% and fluctuates down to 92%. it never gets above 95%. i was concerned because i started out 5% less than capacity i.e. 15% to 80% not 20%.

there is a person on here that did a guide for batteries. basically batteries fluctuate.
 
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GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
However I realized that the brand new MBA is not shipped with a battery capacity of 100%.
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:
 
Comment

tim100

macrumors 65816
May 25, 2009
1,368
0
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:

how about if it never fluctuates up? you start at a lower value than 100% which puts you closer to 80% which is replacement.
 
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GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
how about if it never fluctuates up? you start at a lower value than 100% which puts you closer to 80% which is replacement.
If it drops below 80% before 1000 cycles, it's very likely it's defective, in which case Apple will replace it free, if the Mac is still covered by warranty or AppleCare. There isn't a predictable pattern to health decline. For example, it may drop from 100% to 90% in 3 months, then take another year before it drops as low as 85%. Also, just because a battery reaches 80% health or lower, doesn't mean it's a useless battery. It can still be used, even though it won't last as long as a battery with a higher health.
 
Comment

tim100

macrumors 65816
May 25, 2009
1,368
0
If it drops below 80% before 1000 cycles, it's very likely it's defective, in which case Apple will replace it free, if the Mac is still covered by warranty or AppleCare. There isn't a predictable pattern to health decline. For example, it may drop from 100% to 90% in 3 months, then take another year before it drops as low as 85%. Also, just because a battery reaches 80% health or lower, doesn't mean it's a useless battery. It can still be used, even though it won't last as long as a battery with a higher health.

thank you for the good info.

in your opinion, at what percent less than 100% would you return a macbook that is within its 14 day return policy?
 
Comment

TheRealDamager

macrumors 65816
Jan 5, 2011
1,043
11
I wouldn't even watch it. It's not a factor. If you are getting horrible battery performance after 11 months, THEN have Apple replace it. Just enjoy the machine.
 
Comment

SenorVvangIstMoi

macrumors member
Original poster
Oct 24, 2011
78
4
Bristol, UK
I wouldn't even watch it. It's not a factor. If you are getting horrible battery performance after 11 months, THEN have Apple replace it. Just enjoy the machine.

o_O! Pardon me, you mean the AppleCare could change new internal opponent for you whenever you went to the service counter within the valid period?!
 
Comment

iKnowMr.Jobs

macrumors 6502
Oct 17, 2010
271
95
My 2012 13 inch air is doing the same thing. I'm not super concerned about it. The battery capacity increased from 97.7% to 98.8% after a discharge. I just assumed that it was inaccurate.
 
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GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
thank you for the good info.

in your opinion, at what percent less than 100% would you return a macbook that is within its 14 day return policy?
If I bought a new Mac and the battery was below 90% when I first got it, I would ask them to check it out and possibly replace it. Above 90%, I wouldn't worry about it. That's what the warranty is for.
 
Comment

AlanShutko

macrumors 6502a
Jun 2, 2008
750
132
o_O! Pardon me, you mean the AppleCare could change new internal opponent for you whenever you went to the service counter within the valid period?!

Yes. In fact, even AFTER the warranty period, apple will replace the battery for you for a charge. I think it's something like $125for a MBA battery. It's a fairly quick procedure, think mine was done in a few hours since they had parts in stock. (Rev A MBA.)
 
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tim100

macrumors 65816
May 25, 2009
1,368
0
If I bought a new Mac and the battery was below 90% when I first got it, I would ask them to check it out and possibly replace it. Above 90%, I wouldn't worry about it. That's what the warranty is for.

coconut is now showing 92% battery charge and the apple battery monitor is showing 98%? why are the precent different. the numbers are accurate according to about this mac.
 
Comment

GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
yes. it is showing different percent left on battery percent coconut is 58% and apple is 61%, is calibration needed?
No, as stated in the Battery FAQ, your battery time or percentage remaining is a constantly changing estimate, which varies with the current workload on your system at any given point in time. It isn't 100% accurate. The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.
 
Comment

tim100

macrumors 65816
May 25, 2009
1,368
0
No, as stated in the Battery FAQ, your battery time or percentage remaining is a constantly changing estimate, which varies with the current workload on your system at any given point in time. It isn't 100% accurate. The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.

is it normal that coconut battery is showing a different current charge than the battery mac menu bar i.e. the menu bar is showing 5% larger percent left current charge.
 
Comment

GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
is it normal that coconut battery is showing a different current charge than the battery mac menu bar i.e. the menu bar is showing 5% larger percent left current charge.
As they are both estimates, taken at particular points in time, it's likely they are taken at slightly different times, causing them to vary, as the workload may differ between one estimate and the other. I really wouldn't worry about it.
 
Comment

mattopotamus

macrumors G5
Jun 12, 2012
13,953
4,527
like others said, i wouldn't worry about it too much. For me, my battery has 1 cycle on it and has 78% health....definitely defective!
 
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