How to measure power consumption

Direct measurement during operation

To monitor the laptop's power consumption while it is running, unplug the AC power and run:

# watch -n1 'cat /proc/acpi/battery/BAT0/*'

This requires ACPI to be enabled. The value given is (roughly) an averge over the last minute.

Alternatively, load the tp_smapi module and run the following with AC power unplugged:

# watch -n1 'cat /sys/devices/platform/smapi/BAT0/power_now'

or

# watch -n1 'cat /sys/devices/platform/smapi/BAT0/power_avg'

The former provides the instantaneous power draw, and the latter is (roughly) an average over the last minute. It's OK to use tp_smapi's force_discharge function instead of physically disconnecting AC power.

Note that running on battery power may activate power-saving mechanisms, so unless you take care to deactivate them this does not reflect power consumption under AC power.

Measurement script

See Script_for_monitoring_power_consumption.

Measurement for synthetic workloads

Use the Battery Life Tool Kit tool.

Measurement during suspend

To measure power consumption while the laptop is suspended, use the ACPI sleep power drain test script.

See also

For reducing power consumption, see How to reduce power consumption.