Many people use their MacBook mainly at a desk, with an external display and the charger always plugged in. Then the question arises: is keeping your MacBook always on the charger bad for the battery? The short answer: not really, as long as you know a few things. This article explains what happens to the battery when it is always full, how macOS protects it and when you should still do something about it.
Blue Apple repairs MacBooks in Amsterdam and replaces MacBook batteries.
What happens when it is always full?
A lithium-ion battery wears faster when it stays at one hundred percent for long, especially combined with heat. It does not wear out suddenly, but capacity drops somewhat faster over time. Overcharging is not possible: once the battery is full, charging stops and the MacBook runs directly on the charger.
How macOS protects the battery
- Optimised Battery Charging: macOS learns your routine. If the MacBook is often on the charger for long periods, it holds the battery around eighty percent and only charges fully when it expects you to unplug. Turn it on in System Settings, Battery.
- Battery health management on Intel MacBooks: older Intel models have a similar feature that lowers the maximum charge slightly with heavy charger use.
If the battery icon says "Charging On Hold" or "Not Charging" while the charger is in, that is often this protection, not a fault. See MacBook says "Not charging".
Heat is the biggest enemy
A battery that is full and gets warm wears fastest. So watch for:
- If you use the MacBook closed with an external display, make sure it is not in a closed cabinet.
- Do not put it against a radiator or in the sun.
- Keep the vents clear; a stand that raises the MacBook helps.
Should you let it run down now and then?
That is not needed to "calibrate" the battery. It is good, though, if the battery is used now and then, for example when you work on the sofa for an afternoon. Discharging a bit a few times a month is fine.
Not using it for a longer time
If you go away for weeks and do not use the MacBook, do not leave it at one hundred percent, and not at zero either. Turn it off at about half. See MacBook will not start after a flat battery.
How healthy is your battery?
System Settings, Battery shows maximum capacity and battery health. The cycle count is in System Information, Power. A MacBook always on the charger often has few cycles, but still some capacity loss over time. See battery health and cycles.
More tips
Read saving your MacBook battery for all tips in one place.
A bulging battery
If a MacBook stays on the charger for years in a warm place, the battery can sometimes swell. Signs: the bottom bulges, the trackpad gets stiff. Then stop using it and have the battery replaced. See swollen battery.
What we do at Blue Apple in Amsterdam
We test the battery and replace it if it is worn or swollen. You hear beforehand what it costs. More on our page about MacBook battery replacement.
Frequently asked questions
Can I remove the battery and work on the charger only?
We advise against it. Without a battery a MacBook often runs slower and shuts off if power drops for a moment.
Why does my battery stay at eighty percent?
That is optimised charging. The MacBook only charges fully when it expects you to unplug.
Is a power strip with a switch a good idea?
It is allowed, but not needed. macOS manages charging itself.
