MacBook Pro recharges oddly in Big Sur

QAfter upgrading to Big Sur, my MacBook Pro 16-inch 2019 seems to be having problems recharging its battery. Sometimes when plugged into mains power, it won’t recharge when it shows a battery level well below 100%. Is its battery already starting to die?

AIt’s most likely that your MacBook Pro’s battery is perfectly healthy, and what you’re experiencing is the result of changed charging patterns which have been introduced recently by Apple to extend the working life of the batteries inside its devices.

Many laptops spend most of their working lives connected to mains power, which previously kept their battery at a fairly constant full charge. It’s thought that doing so shortens the battery’s working life, and has been related to problems like battery swelling too. Instead, it’s better to allow the battery to discharge before recharging it. That’s what this recent change in power management in macOS aims to do.

To see this happening, open the Battery pane in System Preferences and check on its history. Rather than seeing a series of bars level at 100% when it’s run on mains power, you should now see the battery discharging slightly, before it’s recharged back to 100%. That pane and System Information give information about the battery’s charge cycles and health which you should find reassuring. If they do suggest a problem, contact Apple Support who should arrange a free replacement if your battery is defective.

The Battery pane has been extended in Big Sur to provide more useful info about its charge levels.