Thinkpad Battery controls on Backtrack

Thinkpad’s smapi needs to be installed and configured to control battery charge thresholds in order maintain good battery life. Here are the things that need to done on BackTrack 4 to set this up

Download tp_smapi from sourceforge

tar it and install it

tar xzvf tp_smapi-0.40.tgz
cd tp_smapi-0.40
make install

Verify the installation by looking for kernal objects (.ko) in


kernel in above line should be your current active kernel version

Once installed you need to modprobe it to load it

modprobe tp_smapi

Alternatively you can make it load during boot up by adding




or by adding it to user start up commands by adding these lines in

modprobe tp_smapi
exit 0

To set the thresholds for starting and stopping battery charging (in percent of current full charge capacity):

 echo 40 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
    echo 70 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh

You can look at Thinkwiki for more usage

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