Many users keep their MacBooks plugged in all day and night. Since they tend to use it at a table or desk, and rarely need to bring it when leaving the house. And while this isn’t a major problem, it can cause longevity issues with the MacBook’s battery. You see, charging lithium-ion battery cells to 100% capacity and letting them sit for hours or even days on end is detrimental to their health. Since constant high voltage and high heat puts stress on the cells and eventually erodes their lifespan. So a battery that would have lasted 1,000 charge cycles, could only last 800. That’s why your iPhone will display a warning message if it’s plugged in at 100% for too long. And even discharge the battery to 99% to minimize long-term damage. But the Mac didn’t have these software protections in place until 2019 with macOS Catalina. If you’ve ever wondered why your MacBook stopped charging at 80%, it’s because of a new feature called Battery Health Management. Which monitors your MacBook’s charging schedule to strike a balance between daily battery life, and battery longevity. For example, if you plug in your MacBook overnight and take it to work by 8am, then it’ll wait to charge past 80% until about 7am. So that it’s fully charged shortly before being unplugged. That way, you enjoy all-day battery life without any negative effect to battery health. If you leave your MacBook plugged in 24/7, then it’ll likely keep its battery at 80% round the clock. So if that sounds like you, it’s smart to make sure the battery health management feature is turned on in the System Preference's Battery settings. That way, you can enjoy the convenience of a persistently powered MacBook without any of the worry. And in the event that you will be taking your MacBook off its charger and want 100% battery, simply click the battery icon and select “Charge to Full Now.” It’ll bypass the 80% limit, and return to it’s normal charging schedule the next day.