low runtime with acer travelmate 290lci (centrino)

[Sebastian Mangelkramer <home@mangelkramer.com>]

hello dear list,
my acer travelmate 290lci (centrino) laptop drives me crazy because the 
runtime when i`m on battery is just about 1h 30min.  i`m using debian 3.1 
sarge with kernel 2.6.7, cpudynd, hdparm with hdd-spindown, ....

even if the cpu runs @50% the runtime is about 1h 30 min.
i don`t know why.

the same laptop running under windoze xp makes more than 4 hours.

are there any tipps or solutions for my problems ?

p.s. all extra hardware ist off (wlan, pcmcia, ...)

best regards,
sebastian