Battery life

My new machine Panasonic Let's Note Y2 will run 7 hours without AC if catalog spec is right.
It may be correct if I use Windows, no wireless, and no extension memory. Unfortunately I'm using Debian GNU/Linux, 11g wireless, and +512MB memory :-)
I installed speedstep-centrino kernel module and cpufreqd package. With wireless, Y2 works 3 hours without AC.
But I was surprised it worked only 3 hours also without wireless! I heard advice from my friend and saw ipw2200 driver README (RTFM, Kenshi). Hmm, I see. Wireless won't stop if I don't shutdown it explicitly. Wireless is working even if I do ifdown eth1 or rmmod ipw2200. Now, I created a small script "wifi" for stop it,

#!/bin/sh
F=/sys/bus/pci/drivers/ipw2200/0000:02:04.0/rf_kill
case "$1" in
start)
	echo 0 > $F
	;;
stop)
	echo 1 > $F
	;;
status)
	cat $F
	;;
*)
	echo "wifi [start|stop|status]"
	;;
esac

After running "wifi stop", Y2 works 5.5~ hours now. Good. It would be better if kwifimanager provide customize configuration rather than implementing dummy code. :-)