MacBooks apparently recognize when they’re always plugged in and do automatic power management and not only stop charging, but let the battery drain a bit so it doesn’t sit at a constant 100% charge.

I had my M1 Air plugged in non-stop for a few weeks and started to get worried about it messing with the battery life. Did some searching and found that it’s totally safe to leave newer MacBooks always plugged in because of the automatic power management system. Sure enough, I unplugged it that day after having it plugged in for those few weeks and the battery charge was at ~75% or something.

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