Leaving a MacBook Plugged In Is Generally Safe, Engadget Reports, With Heat the Main Battery Risk

The widely held belief that leaving a laptop plugged in nonstop will "fry" its battery or reduce its effectiveness no longer applies to modern MacBooks, according to the report. Mac computers use default software to monitor battery life and to adapt to user habits and device power fluctuations, tracking temperature history and charging patterns and modifying charging accordingly. Lithium batteries, which MacBooks and essentially all other laptops use, also carry a high number of charge cycles, and the software uses charging data to calculate when to lower the battery's maximum charge.

Battery health management is switched on by default on Mac laptops running Catalina 10.15.5, released in 2019, or later, the report said. Users who have turned it off can re-enable it through the Apple menu, then System Settings, Battery, Battery Health, and the "manage battery longevity" option. Engadget noted that while avoiding a full charge and keeping it at 100 percent was once considered wise, the system now pauses charging at optimized times, so keeping a MacBook plugged in during use is acceptable.

Engadget said it typically makes no difference whether a MacBook runs on battery or on wall power. The caveats it listed concern less common situations, including home electricity problems such as storms or blackouts, and overheating caused by other factors, along with the occasional unplug as a general practice.

For users concerned about battery condition, the report described a check in System Settings: click Battery in the left-hand sidebar, then look at Battery Health, which usually reads "normal" or "service recommended." Some fluctuation over time is expected, but Apple does not recommend replacement until capacity falls below 80 percent, according to the report.

Battery level also matters when a device is stored for a long period. Engadget cited Apple's guidance that the best way to preserve battery health in that case is to charge the device to around 50 percent. "If you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life," the guide states.

Heat is described as the biggest issue affecting battery health. Working outside on a warm day may call for unplugging the device or moving to a shadier spot, since a computer heating up while charging can negatively affect the battery. The report listed MacBook Air operating temperature ranges as 50 to 95 degrees Fahrenheit, and noted that certain cases or laptop stands can cause a device to overheat while charging. Users who notice a device getting hot are advised to check that its fans are unblocked. Keeping batteries cool, the report said, is one of the easiest ways to help them last longer.

Editor's Summary

Engadget reports that keeping a MacBook plugged in during use is generally harmless to battery health because built-in software manages charging based on temperature and usage patterns. The main risks the report identifies are heat and storing a device fully charged for long periods, with Apple recommending roughly a 50 percent charge for extended storage. Users can check battery condition in System Settings, where Apple advises replacement only below 80 percent capacity.