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View Full Version : Battery on my MBA - 92% after 81 cycles - is this about right??




OceanFrog
May 2, 2013, 01:53 PM
My MBA is around 6 months old with 81 charge cycles. iStat Pro is showing battery health at 92%. Does this look about right??

92% seems a bit low to me, especially as my 2008 MacBook Pro has 519 cycles and battery health is showing at 86%. Both machines are charged and used in similar ways.


EDIT: I'm sure the MBA battery health figure of 92% (6170mAh) is accurate as I've just calibrated the battery



B...
May 2, 2013, 02:22 PM
Battery health will fluctuate and is not a clear indication for the actual battery health, since it depends on how often you recharge and how often you fully drain it.

stchman
May 2, 2013, 02:41 PM
From what I've read, the MBA battery is good for 1000 cycles. So 81/1000 = 8.1%, therefore 92% is where you should be.

Your 5 year old MBP having 86% has to be an error. Lithium-ion batteries life are not that good.

Drew017
May 2, 2013, 02:45 PM
How long do you think your battery lasts on a charge?

B...
May 2, 2013, 02:50 PM
From what I've read, the MBA battery is good for 1000 cycles. So 81/1000 = 8.1%, therefore 92% is where you should be.

Your 5 year old MBP having 86% has to be an error. Lithium-ion batteries life are not that good.

Not quite true. Good for 1000 cycles does not mean until 0% battery health, but it is good for 1000 cycles until 80% (that is the ideal ratio). So 1000 cycles is with 20% degradation, so 1% degradation is 50 cycles. Therefore, to get 8% lower, you have to have 400 cycles. Since he only has 81, that is not right per se.

GGJstudios
May 2, 2013, 02:52 PM
My MBA is around 6 months old with 81 charge cycles. iStat Pro is showing battery health at 92%. Does this look about right??
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.

EDIT: I'm sure the MBA battery health figure of 92% (6170mAh) is accurate as I've just calibrated the battery
The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require calibration (http://support.apple.com/kb/HT1490) like the removable batteries in older Apple notebooks.

The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
Apple Notebook Battery FAQ (http://forums.macrumors.com/showpost.php?p=9875442&postcount=23)

Drew017
May 2, 2013, 02:58 PM
Now that I look at it, this doesn't sound right to me. My MacBook Air (Which I've had about 5 months) has 70 charge cycles exactly. It still has 97% battery health. OP for yours to have 92% you would have to have at least over 220 charge cycles probably if I had to guess.

GGJstudios
May 2, 2013, 03:27 PM
Now that I look at it, this doesn't sound right to me. My MacBook Air (Which I've had about 5 months) has 70 charge cycles exactly. It still has 97% battery health. OP for yours to have 92% you would have to have at least over 220 charge cycles probably if I had to guess.
There isn't a direct correlation between battery health and charge cycles. A battery could have 92% health after 50 cycles or 500 cycles. It varies widely, and the battery health does not decline in a straight line or predictable pattern.

Drew017
May 2, 2013, 04:03 PM
There isn't a direct correlation between battery health and charge cycles. A battery could have 92% health after 50 cycles or 500 cycles. It varies widely, and the battery health does not decline in a straight line or predictable pattern.

Oh ok. Didn't know that ;)

calvol
May 3, 2013, 02:47 AM
Depends greatly on usage patterns, my 2010 13 MBA has 330 cycles and fluctuates between 89 and 94%. I do a total discharge with Caffeine every two months or so, seems to build the health count back up.

GeekGuys
May 3, 2013, 03:21 AM
I have a 2007 MB White that still has 94% battery health reported and I still get about 3.5 hours+ on a full charge doing normal stuff with WiFi and Bluetooth both active. It has 700+ charge cycles and is still going strong.

My 2012 MBA showed 98% when new, then within a month or so dropped down to 93%. It has stayed there for 160 charge cycles so far. Doesn't change much (up and down by 1 or 2 %). I generally use it always on power (as I can use intensive applications that drain battery in an hour or two) and once a week or so will use it on battery only to drain and fully charge.

Not sure it makes any difference but it feeds my OCD :D

I think the key thing is, does it drop or does it stay pretty much the same? Check it with CoconutBattery (or similar) once a month or so if it makes you happy.

GGJstudios
May 3, 2013, 09:26 AM
I do a total discharge with Caffeine every two months or so, seems to build the health count back up.
once a week or so will use it on battery only to drain and fully charge.
You never need to fully drain the battery, and it's not good for the battery to do so regularly.

Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug any time you need to, regardless of the charged percentage, and you never need to completely drain your battery. Just make sure you don't run on AC power exclusively, as your battery needs to be used regularly to stay healthy.

Orka
May 4, 2013, 06:43 PM
What do you think of my battery?


http://img560.imageshack.us/img560/1594/2013050533733.png (http://imageshack.us/photo/my-images/560/2013050533733.png/)

Uploaded with ImageShack.us (http://imageshack.us)

Orka
May 4, 2013, 06:55 PM
You never need to fully drain the battery, and it's not good for the battery to do so regularly.

Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug any time you need to, regardless of the charged percentage, and you never need to completely drain your battery. Just make sure you don't run on AC power exclusively, as your battery needs to be used regularly to stay healthy.


I think that Apple once and for all should address if it is OK to completely discharge the battery or not and specifically state either don't or do.
I often hear that it's not ok, and only source people provide to base this claim on is some weird and little known batteryuniversity link, where they state it.
No laptop manufacturer (Apple included) doesn't state this, may be i'm wrong, but i assume it shouldn't be a problem (wouldn't they warn about it otherwise?).

dannyp1996
May 4, 2013, 08:07 PM
I thought I should offer my experience on this as I have been recently been keeping more of an eye on things (since I started collage and use my Mac on battery more).

I have a 13" 2010 MacBook Pro (the last of the C2D MBPs) which has had what I would call exceptionally heavy usage in the 2.5 years since purchasing. iStat Pro tells me I have 834 cycles with 84% battery health. I take little care of the battery, have never calibrated it, and its current performance means that it will withstand a full collage day without need for recharging (the starting life of the battery was roughly 10.5 hours).

oldtime
May 6, 2013, 02:17 PM
My 2012 MBA is at 95%/19 cycles, FWIW. I unplug and use it on the go a few times a week.

OceanFrog
May 7, 2013, 08:37 AM
Thanks for all the replies guys. iStat is now showing 94% after 82 cycles.

How long do you think your battery lasts on a charge?

Battery had a full charge this morning. I've been using it for the last 3 hours at 80% screen brightness, Paired with bluetooth keyboard (Apple) and mouse (logitech Performance MX), external HDD plugged in, external monitor also plugged in. WiFi has also been on constantly. I've been using Skype, Word, Excel, Calendar, Twitter, Chrome, and Safari. There were also a few TM backups over the 3 hours.

Battery level is now showing (after 3 hours constant use) at 15% (estimated 30 minutes remaining). That looks like 3.5 hours total battery use under the conditions I've described.

Does this sound correct?

Coffee Minutes
May 7, 2013, 08:59 AM
Mid-2012 MBA Purchased in AUG 2012

iStat reads:

HEALTH: 89%

CYCLES: 125


Does this seem okay/average????

GGJstudios
May 7, 2013, 11:08 AM
Mid-2012 MBA Purchased in AUG 2012

iStat reads:

HEALTH: 89%

CYCLES: 125


Does this seem okay/average????
Yes. Read post #6.

Drew017
May 7, 2013, 11:25 AM
Thanks for all the replies guys. iStat is now showing 94% after 82 cycles.



Battery had a full charge this morning. I've been using it for the last 3 hours at 80% screen brightness, Paired with bluetooth keyboard (Apple) and mouse (logitech Performance MX), external HDD plugged in, external monitor also plugged in. WiFi has also been on constantly. I've been using Skype, Word, Excel, Calendar, Twitter, Chrome, and Safari. There were also a few TM backups over the 3 hours.

Battery level is now showing (after 3 hours constant use) at 15% (estimated 30 minutes remaining). That looks like 3.5 hours total battery use under the conditions I've described.

Does this sound correct?

Yeah… that sounds about right. Especially if you use it at 80% screen brightness. I usually keep my MBA at around 1-3 notches above lowest max brightness (helps a lot with the battery)

derohan
Jun 3, 2013, 08:56 AM
My 2012 isn't doing so good anymore :(

414961

Look alright?

B...
Jun 3, 2013, 08:59 AM
My 2012 isn't doing so good anymore :(

414961

Look alright?

Not really, but as I said before, it fluctuates. How is your battery life?

CoMoMacUser
Jun 3, 2013, 09:02 AM
How do I find the number of cycles? Thanks.

B...
Jun 3, 2013, 09:03 AM
How do I find the number of cycles? Thanks.

Coconut Battery or iStat Pro.

derohan
Jun 3, 2013, 09:07 AM
Not really, but as I said before, it fluctuates. How is your battery life?

Well I used to be able to watch 1080p mkv's for a good 6-7 hours after the 10.8.X update that fixed the battery life

Now I'm getting around 5, and like OceanFrog said, under his conditions, I get aroud two and a half hours.

CoMoMacUser
Jun 3, 2013, 09:55 AM
Coconut Battery or iStat Pro.

Thanks. I thought maybe this feature was built into ML.

GGJstudios
Jun 3, 2013, 10:22 AM
Thanks. I thought maybe this feature was built into ML.

It is built in. You don't need a 3rd party app to determine battery cycle count.

Mac notebooks: Determining battery cycle count (http://support.apple.com/kb/ht1519?locale=en_us&viewlocale=en_us)

This link and much more information can be found in the Battery FAQ in post #6.