piotrn95 wrote:
My MacBook Pro is plugged into a power source all the time. When I turn on the computer in the morning, I can see on the login screen that the battery is 97-99% charged. Once I log into my account, the charge level shows up correctly - 100%. Is it a battery problem (or other hardware problem) or could it be a software bug? SMC and PRAM were reset - also without effects. The diagnostic test showed no errors. System report shows: battery status normal. The update so far has not fixed the problem. Completely deleting data from the disk and reinstalling the system did not help either. The iStats Menus app shows battery health at 91% (6672 mAh of 7336 mAh) with just 60 battery charging cycles.
MacBook Pro 15,4" 2018 MR932ZE/A A1990
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Unfortunately you do not say what macOS you are running or what exact Mac, however
I can say since macOS Catalina 10.15.5 introduces battery health management, a feature designed to improve the lifespan of your Mac notebook's battery.
The Battery Health button appears in >SystemPreferences>Energy Saver/“Battery” in the newer macOS —this feature is limited to Mac laptops with Thunderbolt 3 ports. That equates to all MacBook Pro models released since late 2016 and the Retina-capable MacBook Air models released since 2018.
With the release of macOS 11.0.1 Big Sur see >System Preferences>Battery
You do not have to micro manage battery health, it will learn as it goes— and it is not linear. If you are near the mains leave it plugged in, no harm. If you need the portability then use the battery.
I have seen it hold the charge at 94%, 84% and/or 72% as it see fit.
About battery health management in Mac notebooks https://support.apple.com/en-us/HT211094