How long dose a 9 cell battery last?

[ccookie66]

Hello, my Thinkpad t40 battery right now last about 20 minutes. I'm not sure how many cells it has, but I want to buy a new 9 cell battery for it. How good is a 9 cell battery? How long dose it last? I don't really know much about batteries or the 3, 6, or 9 cell battery stuff.

[Raceboy]

On my 14,1 inch XGA T42 with Radeon 7500 and undervolted Dothan (1,86 GHz 750 running at 1,4 GHz max with 400 MHz FSB) my almost new Panasonic 9cell (worn 6%) holds around 6,5 hours with wireless on and screen brightness around half. Also this laptop has 5400 rpm HDD and no optical drive. Planning to swap R51 Intel GPU planar to reduce power consumption even more. If I could just find palmrest with no touchpad too....

Instead on my other T42 with 15" SXGA+ IPS FlexView and 2,0 GHz Dothan together with 7K60 the same battery holds around 4-4,5 hours.