Category Archives: Hardware

Lenovo X61s Battery Life

I have a 2y old Lenovo X61s running ubuntu jaunty. Ever since I acquired I’ve been rather unimpressed by battery life-time which seems to be max 1.25-1.5h (2h if I’ve just got it on but not doing anything). This lifetime is achieved when:

  • Switching off wifi, bluetooth, usb etc
  • Switching laptop mode on
  • Turning down backlight to around 30% or below
  • Plus anything else powertop suggests

I should note I’m usually doing some kind of actual work though nothing too intense (if I start running lots of tests that use the DB, or using a browser battery life falls). Under these conditions I can get power usage down to 11-12W though more usual during actual work is 12-14W.

I’ve finally got around to doing some googling around (I’m thinking of getting another battery) and discovered:

  • There are three battery types for X61s:
    • Thinkpad X6x 4 cell slim line battery 28.8 Watt hours (3 hours @ 9.3 W/hr)
    • Thinkpad X6x 4 cell cylindrical battery 37.4 Watt hours (4 hours @ 9.3 W/hr)
    • Thinkpad X6x 8 cell battery 74.8 Watt hours (8 hours @ 9.3 W/hr)
  • I almost certainly have 4-cell slimline (least power).
  • According to this useful thread my battery life is poor but within the parameters (in particular 2.5h battery life mentioned seems to depend on power usage around 9.5w)

Based on these calculations and 8-cell battery (409g and around £60-140) should get me around 3h battery time. An improvement but not amazing.