Linux: Tips for Improving Battery Life. Intel CPUs

[pmn1111]

Summary: Linux Battery Saving options are not so automatic. Battery life may be poor. These steps may help.

Details: While modern Intel CPUs use P-States to keep CPU power levels optimum, I have found it does not take into account if the PC is running on AC or Battery Power. This causes rapid power drain - even when doing mundane tasks (i.e. browsing, email, writing, not gaming).

Solutions: 

1. Activate POWERSAVE governor (Many kernel configurations have PERFORMANCE as default)
2. Apply POWERTOP application --auto-tune option

And some more obvious ones

1. Dim screen
2. Disable unused features, i.e. Bluetooth
3. Suspend unused system processes

These items more than doubled available battery time from just under 2 hours, to over 4 hours.. The powersave governor reduces the CPU frequency, and the powerertop application optimizes acpi settings.

These commands may help (your distro may have init scripts for this, but in case:

As root:

$ echo "powersave" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

courtesy Slackware rc.cpufreq init script

As root

$ powertop --auto-tune

YMMV but I hope this information is useful. Perhaps there are comparable settings for AMD processors.

References: About Intel P-States , Kernel Scaling Governors , Powertop Documentation and Download