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MacBook Air 13", Early 2015
macOS Monterey 12.4 (21F79)

I recently got the battery replaced. I am observing a difference in charging status depending on where I look. I never bothered to check these with the previous battery.

When the light on Magsafe power adapter goes from amber to green, the battery status on the Menu Bar says 100% charged. But if I look at System Information > Power, it shows:

Fully Charged: No
Charging: Yes
State of Charge (%): 100%

coconutBattery app reports:

Current Charge: 6871 mAh
Full Charge Capacity: 7151 mAh
Charge level: 96.1%
Design Capacity: 7150 mAh
macOS Battery Status: Good

What can cause this problem? Does it look like a hardware or a software issue?

Full Details from System Information:

Model Information:
Serial Number: XYZ
Manufacturer: SMP
Device Name: bq20z451
Pack Lot Code: 0
PCB Lot Code: 0
Firmware Version: 511
Hardware Revision: 000a
Cell Revision: 1200

Charge Information:
Fully Charged: No
Charging: Yes
Full Charge Capacity (mAh): 7151
State of Charge (%): 100

Health Information:
Cycle Count: 9
Condition: Normal

AC Charger Information:
Connected: Yes
ID: 0x07a1
Wattage (W): 45
Family: 0x00ba
Serial Number: 0xXYZ
Charging: Yes

Edit 1: I did the following:

  1. Allowed the battery to drain all the way.
  2. It stayed at 1% for some time and then the MacBook turned off on its own.
  3. I let it be that way for 8-9 hours.
  4. Charged the battery to 100%.
  5. Switched on the MacBook. It restored the apps and open windows (does that mean it just went to deep sleep?).

The original problem that I reported above is still seen.

Edit 2: As the battery level goes lower, the difference between values shown in Menu Bar and System Information keeps reducing. For example, when Menu Bar first shows 100%, the difference is around 4%. When the battery level reduces to around 25%, the two values shown are pretty much the same. Not sure what this really means.

oyenamit
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    Did you do a full charge + discharge cycle after battery change? To my knowledge, MacBooks use some FuelGauge chip from TI to estimate their state of charge. Those BQsomething chips need to get to know a new battery by meeting an upper and lower charge limit. Before that, they can give strange, even contradicting results, especially considering that the OS declares the battery as full while it continues to charge very slowly. – Philippos Jun 10 '22 at 13:33
  • @Philippos I have updated the post with details of what I tried with full charge + discharge cycle. But the problem is still there. Anything else that I can try? – oyenamit Jun 11 '22 at 20:03
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    What is the problem, other than slightly inconsistent data? Is the battery performing within your expectations? – benwiggy Jun 11 '22 at 20:15
  • @benwiggy The inconsistent data is the only problem - the OS is reporting battery level as 100% while still showing Charging as Yes. I am not sure if this is a defect or not (battery condition is shown as Normal). – oyenamit Jun 11 '22 at 20:33
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    Was this battery replaced by a shop, or was it DIY? If the former, then you could take it back and ask them to check it. – benwiggy Jun 12 '22 at 07:47
  • @benwiggy It was replaced by Apple Service. I found an old question with similar issue. Before I take it to Apple, I wanted to check with others if this really is an issue. I suspect Apple's standard response to something like this would be to replace the battery again and/or reinstall the OS. – oyenamit Jun 12 '22 at 14:38
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    Reinstalling the OS is over-rated as a fix for anything: the bit that gets re-installed is read-only, and secured. Chances are that nothing there has changed. It's everything EXCEPT the OS that causes problems: pref files, caches, configs, and user software. At best, you could try an SMC reset https://support.apple.com/en-gb/HT201295 But really I'd just file this as an inconsequential oddity and move on. – benwiggy Jun 12 '22 at 14:43
  • @benwiggy SMC reset also did not help. As you said, I can learn to live with this minor glitch. Thanks! – oyenamit Jun 13 '22 at 18:29

1 Answers1

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Coconut Battery tells you that the current Charging capacity is 96.1% of the Design Capacity.

System Information is showing you that the battery is 100% full -- whatever its current capacity may be.

There is perhaps some confusion caused by the term "Full Charge Capacity", and what that means.

The laptop's power management will vary the full charge level somewhat across a number of cycles, as a means of preserving the life of the battery. So after a few more cycles, you may find that the Current Capacity is higher than 96.1%.

Apps that provide detailed information can be useful for trouble-shooting, but they just as often provide more information for you to worry about.

benwiggy
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  • I used coconutBattery only to further check the state of the battery and its charge. But what really bothered me initially was what System Information was reporting: Fully Charged: No, Charging: Yes, State of Charge: 100%. Is that really normal? – oyenamit Jun 10 '22 at 13:16