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I bought a new Mac, a little over a month ago. It has exactly 15 battery cycles now (after my use, of course). So, definitely, a new battery.

But, my problem is that I can see, through CoconutBattery and iStats that it can only retain about 8100mAh. They state my battery is with a health of 92~93% (supposedly, this battery is rated around 8700mAh when new). I confirmed on Apple stats that it retains 8100mAh, but Apple tells me nothing about the total expected capacity.

Is there a problem with my battery, or is this just a normal manufacturing variation?

They all state the condition is normal. But I find it weird that it won't retain 100% or even close to that, like 97, 98, 99%.

I can only imagine in a year, this dropping to below 90, like around 80%. I had other Macs that retained that over the period of like 3 years or more.

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  • Which Mac exactly? (Air, Pro, screensize, year?) – jksoegaard Dec 31 '20 at 15:33
  • Does it make any difference? It's a Macbook Pro 16 inch, latest model. – lucasarruda Dec 31 '20 at 15:55
  • I wouldn't ask if it didn't make a difference... a 13" MacBook Air doesn't have the same battery as a 16" MacBook Pro for example. – jksoegaard Dec 31 '20 at 15:59
  • Right, I know batteries are different per computer. I am asking because I thought you had some insight that one could be more defective than the other. In this case, both softwares are detecting a smaller mAh according to expected battery specs for this model. – lucasarruda Dec 31 '20 at 16:22
  • Just for comparison, I too have a 16-inch 2019 MacBook Pro, that is older than yours, with a Cycle Count of 4 because I use it mostly like a desktop and in clamshell mode attached to a large display. It shows the same Design Capacity, 8790 mAh, and 92.6%. – user3439894 Dec 31 '20 at 16:46
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This happens regularly and we don’t have issues with them at work and often see a pretty wide range of FCC numbers initially. The measurements are precise but not accurate over short time periods. I would track use every three months and if at the 11 month period get a second read by Apple. They will have service notes for the battery diagnostic when new and also at almost a year so that will tell very accurately what the overall lifespan is.

If you haven’t contacted AppleCare and had them run one remote battery diagnostic, do that late January after the rush of holiday help requests has died down. Unless it’s popping a warning or you can’t get reasonable life, there’s no rush to get the first scan done.

Here are some past posts on whether any one measurement is predictive and how to handle end of warranty situations.

I would use that battery hard for a week or two (empty to full) and you’ll know it’s performing or not without needing any special calibration steps that were used in the past.

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  • Thanks @bmike. I just thought it was weird that such a new computer has like less than 95%. I would expect some variation but not by almost 10%. I am following it closely and will try to have a diagnostics before it hits the 1-year warranty. Will try also, one more time, to fully discharge and charge back a few more times, even if that "eats" more cycles, so I know that this number is real. – lucasarruda Dec 31 '20 at 16:27
  • Batteries don’t behave like a liquid container where measurements are all linear. If your small chip that measures voltage is off 3% it can miss the FCC number by a lot more but mean nothing. The charge to voltage curves are non-linear so that sensor is less accurate at full and designed to work at the low to mid range and cause the charge to taper off past 85% full, not be perfect for measuring a “full new battery”. @lucasarruda you will know by other means if you didn’t get an excellent battery than this one measure. – bmike Dec 31 '20 at 16:38
  • Thanks for clearing @bmike! I guess I just have to keep a close eye to follow how it evolves from here. – lucasarruda Jan 2 at 0:29
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From what I remember reading, it's usual for there to be some small reduction from 'design' capacity in the first couple of months, and then it should be steady. If you are losing any more than c 93% over the first six months, then I would take it in to be looked at.

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  • But it's never going up, right? I might have 93, or 92% in 6 months. But never like 96%, correct? – lucasarruda Dec 31 '20 at 19:42
  • @lucasarruda No, it won't go up. – benwiggy Dec 31 '20 at 22:28
  • Right. So I guess if it doesn’t go down so much that means it’s not defective. But if it does, then it’s probably 93% now because it’s ended defective, I guess. Thanks @benwiggy – lucasarruda Jan 2 at 0:27
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No, It is not normal for a new MacBook to have less than 100% battery. U should contact support and get your product replaced. check this from apple support

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    Although the document you quote says If your Mac won't charge to 100% If you use optimized battery charging in macOS Big Sur or use macOS Catalina or earlier, occasionally the battery might not show a full charge (100%) in macOS, even after the power adapter has been connected for an extended period of time. This behavior is normal and helps prolong the overall life of the battery. So it could be normal – mmmmmm Dec 31 '20 at 17:14
  • I agree only with contact support to be sure your new Mac is in spec. I’m not going to -1 this, but the rest seems premature. FCC isn’t a relevant or accurate single measure. Despite the measurement being precise, more goes into a proper determination of fit for use. – bmike Dec 31 '20 at 17:25
  • Just trying to make it clear: I don't have less than 100% battery because it's optimally charging. I didn't even upgrade to Big Sur yet. My battery is charging to 100%. The problem is that this 100% is equal to 8200mAh and this particular MacBook Pro should have 8790mAh by design. So, that's why iStats and CoconutBattery state that I have 93% battery health. – lucasarruda Dec 31 '20 at 19:41

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