TLP is a battery management tool that is by default optimized after Powertop’s recommendations. To install TLP together with acpi_call (for Thinkpads),
sudo pacman -S tlp acpi_call
After installation we need to enable the service and we can check the tlp battery status,
sudo systemctl enable tlp.service
sudo tlp-stat -b
Here we can see,
/sys/class/power_supply/BAT1/charge_control_start_threshold = 0 [%]
/sys/class/power_supply/BAT1/charge_control_end_threshold = 100 [%]
The default values are optimized for runtime however not for battery lifespan (this is a trade off). The values in these files can be changed to more appropriate values for battery health, such as 40 and 80. Note that these levels do not control the discharging of the battery which only depends on if the AC is connected and/or the laptop is switched on. This means that if the AC is plugged in and the battery level is higher than the threshold it will not discharged down to the threshold level.
The same can also be done with,
sudo tlp setcharge 40 80 BAT1
Note that these changes are only temporary. If you want permanent changes you’ll need to
configure the config file at /etc/tlp.conf and set,
START_CHARGE_THRESH_BAT1=40
STOP_CHARGE_THRESH_BAT1=80