If your portable Mac has a removable battery, calibrate the battery to ensure that you get the longest running time. When your purchase your Mac, you should calibrate its battery in the first week and then recalibrate it every two months. If you use your Mac infrequently, it’s best to recalibrate the battery at least once a month.
If your portable Mac has a built-in battery, you don’t need to calibrate the battery.
Plug in the power adapter and fully charge the battery.
When the battery is fully charged, the light on the power adapter connector changes to green. If your Mac is on, click the Battery icon in the menu bar to check whether your battery is fully charged.
Keep your Mac plugged in for two hours.
During this time, you can use your Mac or turn it off, as long as the power adapter is plugged in.
Disconnect the power adapter. If your Mac isn’t already turned on, turn it on. Then keep your Mac on until the battery runs down and your Mac goes to sleep.
You can use your Mac during this time. If you don’t use your Mac, make sure it doesn’t go to sleep before the battery runs down.
Prevent your computer from sleeping
If you continue to use your Mac and you see the low battery warning, save your work and close all apps. Keep your Mac turned on until it goes to sleep when the battery runs down.
After your Mac goes to sleep, turn it off or allow it to sleep for five hours or longer.
After five or more hours, connect the power adapter and leave it connected until the battery is fully charged.
You can use your Mac during this time.