Battery Charge Thresholds

Important

  • Battery charge thresholds, discharge and recalibration are currently only supported for IBM/Lenovo ThinkPads
  • Any other Lenovo laptop models including IdeaPads and all other laptop brands are not supported
  • TLP 1.3.1 does not support the kernel’s natacpi implementations for Asus and Huawei laptops because of differing sysfiles

START/STOP_CHARGE_THRESH_BATx

START_CHARGE_THRESH_BAT0=75
STOP_CHARGE_THRESH_BAT0=80

START_CHARGE_THRESH_BAT1=75
STOP_CHARGE_THRESH_BAT1=80

Set battery charge thresholds for main battery (BAT0) and auxiliary/Ultrabay battery (BAT1). Values are given as a percentage of the full capacity. A value of 0 is translated to the hardware defaults 96/100%.

Note

  • Charging starts upon connecting AC power, but only if the charge level is below the start threshold (START_CHARGE_TRESH_BATx)
  • Charging stops when reaching the stop threshold (STOP_CHARGE_TRESH_BATx)
  • If, however you connect the AC adapter when the charge level is above the start threshold, then it will not charge

Hints:

  • Thresholds always go with a lower usable battery capacity, therefore the settings are disabled by default and must be enabled explicitly by removing the leading #
  • ThinkPad T420(s)/T520/W520/X220 (and all newer models): check Erratic Battery Behaviour
  • For further questions concerning charge thresholds please visit the FAQ: Battery Features

RESTORE_THRESHOLDS_ON_BAT

RESTORE_THRESHOLDS_ON_BAT=1

Restore configured charge thresholds when AC is unplugged:

  • 0 – disable
  • 1 – enable

Default when unconfigured: 0

Hint: after the commands tlp fullcharge/recalibrate the charge thresholds will stay at the hardware defaults 96/100% until the next reboot. Use this feature to restore them prematurely.

NATACPI/TPACPI/TPSMAPI_ENABLE

NATACPI_ENABLE=1
TPACPI_ENABLE=1
TPSMAPI_ENABLE=1

Control battery feature drivers:

  • 0 – disable
  • 1 – enable

Default when unconfigured: 1 (all)

See also

  • tp-smapi – tp-smapi documentation at thinkwiki.org
  • tpacpi-bat – tool to provide battery charge thresholds and recalibration for newer ThinkPads (X220/T420 and later)