Problem:

What is battery calibration, and how do I do it?




Solution:


Over time, the minimum and maximum charge readings of the battery may become inaccurate. The result will be that sometimes the battery reads a less than 100% charge, but is no longer charging; or the computer shuts down too early, while actually there is still some charge left in the battery. One of the main causes of readings becoming inaccurate is battery wear (see above).

To fix this, you can run battery calibration. Some notebooks have an option to do that in the BIOS. For those notebooks, reboot and enter BIOS. Look for the "Start battery calibration" option or something similar. The BIOS will then charge the battery to full, and then ask you to unplug the computer and leave the battery to discharge to empty; do so. When the battery is discharged, the calibration is complete. Restarting the notebook into the operating system should give you accurate charge readings.

For notebooks that don't have the option, you can sometimes replicate it manually. Charge the battery to full, then unplug the computer and turn off all the battery alarms (Low Battery and Critical Battery). Let the battery drain completely. Start Windows and recharge the battery. Reboot one more time. With any luck, your battery meter is calibrated after this procedure.

Do not abuse this option, as Lithium-Ion batteries don't actually like fully discharging them to empty; this adds some wear to the battery (more than the ordinary usage patterns).