Battery Lifetime Lenovo T61 with 7-Cell-Battery
So after used my T61 for quite a while now I wanted to give a update about my experience with the battery lifetime of this laptop. In almost every review about the T61 the biggest issue was its short running time on battery. And that’s at least not totally wrong. The T61 won’t ever become a battery life wonder… But after taking proper care about the Lithium ion following the Maintenance Guide on thinkwiki.org, with the help of the nice Kernel module tp-smapi, I’ve got a maximum capacity of about 74W.
Experimenting with bleeding-edge kernel sources like kamikaze-sources and its successor zen-sources and following some tips under www.lesswatts.org leaded to an energy consumption of about 16-18Wh with WiFi and even 14Wh without. Of course you get this values only with darkened backlight (use xbacklight instead of /proc/acpi/ibm/brightness see here why).
So all this together gives me something like 3 to 3 1/2 hours of surfing and working in the Uni… of course much lesser if I compile the latest KDE :-). But I thinks that are pretty reasonable results for an laptop with this performance.
JAclar's Weblog 
P. Aman said,
September 22, 2008 at 19:38
I’ve a T61, too, and without wifi and 40% backlight i get 11-12Wh. And this with the hdapsd waking my cpu 50 time per secound, 150 wakeups alltogether. My T61 Edition comes with this outstanding 9 cell battery (outstanding in its very meaning, its stands out 😉 ), and i get 6h with 100% backlight, 7.5h with 40% and even 8.5h with 10% (but this is suicide for your eyes), but without wifi. Can’t say what the battery time is a problem on my T61, but i know it highly depends on the edition.