I used zen kernel patchset for a long time which included tp_smapi patch. Recently in zen-stable tp_smapi was removed as "We no longer need tp_smapi as of 2.6.36 - the in-kernel thinkpad acpi support is better.". How to port following code to in-kernel thinkpad acpi:
echo 40 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
echo 40 > /sys/devices/platform/smapi/BAT1/start_charge_thresh
echo 60 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh
echo 60 > /sys/devices/platform/smapi/BAT1/stop_charge_thresh