How to "calibrate" a new battery
When a Mac laptop's battery has been replaced with a new battery, the laptop's battery gauge must be recalibrated so it will show an accurate indication of battery strength left.
This is sometimes erroneously referred to as "calibrating the battery." It is not the battery that is being calibrated, but the data the laptop knows about how long the battery will last. Obviously, with a new battery, that information will be different than with the old battery, which was most likely replaced due to poor battery life.
The process is quite simple, yet for some reason, there is no Apple support article on the subject as far as I can tell. Here's what I did after having the battery replaced on my 2013 MacBook Air A1466.
- Charge the battery fully, and leave on charge for another 2 hours.
- Change all the Battery Settings and the Desktop Screen settings to consume maximum energy
- Let the laptop battery run down completely. This may take several hours.
- Leave the laptop off and unplugged overnight to make sure the battery is fully drained.
- Charge the laptop back up and reset the Battery and Desktop settings to normal values.
For details on this process for newer Mac laptops, I found this simple guide: https://www.newertech.com/batteries/power-calibration-guide/
