Force laptop to run from battery while plugged in?

[matt_garman]

Does anyone know, under Linux, how to force the laptop to run from the battery, even while it's plugged into the AC outlet? Or, does anyone know of any software that does the same?

Windows or the IBM power management software had a program that would "excercise" the battery, i.e. deliberately run from the battery while plugged-in, and keep the charge levels within some range (never fully drained, never fully charged). This is supposed to extend the life of the battery.

I'd like to do the same in Linux. I'd also like to do some power consumption testing remotely (so the laptop needs to stay plugged in).

Thanks!
Matt

[matt_garman]

Someone on the linux-thinkpad mailing list was kind enough to point me to thinkwiki.org: Tp smapi.

Basically, you can install the tp_smapi kernel module and have control over some aspects of your battery.

-Matt