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Sowelu

macrumors 6502a
Original poster
Aug 15, 2008
747
872
New York City
Hi all -

So, I have three M2 MacBook Airs (two 13" and one 15") - they all have about the same amount of use and charge cycles, but the battery in one of the two 13" MacBook Airs seems to be suffering from premature battery degradation (with few battery cycles) as you can see in the battery apps below:

Screenshot 2024-02-11 at 2.46.03 PM.png


My other MacBook Airs have either the same amount of charge cycles or more, but their batteries are still at 100% 'health'. Is this just a bad battery, or is macOS just not reading the health correctly? Losing 9% of the battery's capacity after only about 30 charge cycles (it's been stuck at 91% for months) doesn't sound right to me, especially when my other MacBook Air's are still at 100%.

I remember (years ago) that there were ways to recalibrate the battery discharge rate with macOS, and then there were times when you'd have to reset the power settings (PRAM?), but I am not sure if this is still a thing on modern Macs. I've tried letting it fully discharge until it goes into deep sleep for a while then charging it back up without using it, but no change.

Anyone else having the same issue with their M2 MacBook Air's battery, or know of a resolution to this other than waiting for it to dip below the AppleCare+ threshold and getting the battery replaced?
 

jdb8167

macrumors 601
Nov 17, 2008
4,664
4,340
Battery chemistry is somewhat of a crapshoot. It is not an exact science. And the total number of battery cycles is not the sole determinate of why battery health declines. Heat is a major factor as is how deeply you drain the battery. Cycling between 80%-20% is probably going to yield better battery health over time than if you go from 100%-0% every cycle.

My M2 MacBook Air bought in July 2022 has 245 cycles and is at 86.5% health according to current full charge capacity value over design capacity value. Apple's battery settings panel claims it is at 91%. These numbers seem reasonable to me but not spectacular. But mostly I don't worry much about it as I'm likely to upgrade to a new MacBook within a year or two.
 
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JPack

macrumors G5
Mar 27, 2017
12,320
22,662
As mentioned, temperature is a big contributor. Another is state of charge. Were the notebooks kept at at or near 100% or 0% SoC? Cycles is only one factor when looking at battery health.
 
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halledise

macrumors 68000
Hi all -

So, I have three M2 MacBook Airs (two 13" and one 15") - they all have about the same amount of use and charge cycles, but the battery in one of the two 13" MacBook Airs seems to be suffering from premature battery degradation (with few battery cycles) as you can see in the battery apps below:

View attachment 2348521

My other MacBook Airs have either the same amount of charge cycles or more, but their batteries are still at 100% 'health'. Is this just a bad battery, or is macOS just not reading the health correctly? Losing 9% of the battery's capacity after only about 30 charge cycles (it's been stuck at 91% for months) doesn't sound right to me, especially when my other MacBook Air's are still at 100%.

I remember (years ago) that there were ways to recalibrate the battery discharge rate with macOS, and then there were times when you'd have to reset the power settings (PRAM?), but I am not sure if this is still a thing on modern Macs. I've tried letting it fully discharge until it goes into deep sleep for a while then charging it back up without using it, but no change.

Anyone else having the same issue with their M2 MacBook Air's battery, or know of a resolution to this other than waiting for it to dip below the AppleCare+ threshold and getting the battery replaced?
for comparison to yours …

Screen Shot 2024-02-13 at 08.57.28.png Screen Shot 2024-02-13 at 08.58.59.png
 
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diego.caraballo

macrumors 6502a
Oct 18, 2013
604
1,560
I noticed on my too.
Nothing to do unfortunately and while Apple does sell the battery, the replacement is the most cumbersome ever.
You even need to re-apply thermal paste in order to complete the repair...

Mine (Oct/23 vs now). Currently doing a calibration.

Screenshot 2024-02-12 at 19.22.42.png
 
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Sowelu

macrumors 6502a
Original poster
Aug 15, 2008
747
872
New York City
Wow, 500+ cycles - that to me is inline with your battery degradation.

As for heat, the MacBook Air in question is always running relatively cool. The only time I see the temp go up is when there are system updates installing. I don't think I've ever seen this Air go over 70c.

Since battery saver (or whatever it was called) is now baked into macOS, it can't be due to the way it charges and discharges from 0-100, so perhaps it's just a bad battery, or it's kept plugged in too often.
 

Sowelu

macrumors 6502a
Original poster
Aug 15, 2008
747
872
New York City
I noticed on my too.
Nothing to do unfortunately and while Apple does sell the battery, the replacement is the most cumbersome ever.
You even need to re-apply thermal paste in order to complete the repair...

Mine (Oct/23 vs now). Currently doing a calibration.

View attachment 2348767
Yeah, I saw what the process was on iFixt and was like, nah. As someone else mentioned, I'll probably be on the M3 Air by the time this becomes a problem. I just thought it was odd as compared to my other MacBooks.
 
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Rustyfan

macrumors newbie
Aug 22, 2019
9
8
Woodstock, IL
Maybe I take care of my batteries better than most, my launch day space grey 13" M2 Air is chugging right along.
 

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halledise

macrumors 68000
Maybe I take care of my batteries better than most, my launch day space black 13" M2 Air is chugging right along.
91 cycles - there’s the reason.
mine is same vintage (june.22) yet with 500+ cycles, the battery is 89% max.
after 3 years or so it’ll be a new battery - no real biggy.
(ps. 13” M2 MBA came in midnight, not space black - that's reserved for M3 MBPro Pro)
 

rachislenska

macrumors member
Jun 22, 2014
74
34
I know many wont agree with me here. I don't know if it applies to your case also. One of the common themes with early battery degradation is using the MacBook plugged in. Yes, some software which optimises charging may be used but I think these devices are made to be used on battery. Constant use by keeping it plugged in does more harm than good even with battery optimising softwares. It maybe also be due to the heat generated by keeping it plugged in, added to the constant high state of charge which is anyway harmful for lithium batteries.

Finally when a device is made with such amazing battery life, why not just utilise it?
 
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