I picked up an X250 last year w/ the extended 6-cell battery primarily for the better battery life.
With TLP setup, I'm able to get 8-10hrs of battery life w/o issues (I've gotten up to 13hrs if all I'm doing is editing text).
According to powertop, I can get power usage to go to over 18W on full load (100% CPU/DRAM, 100% display backlight), but under my normal setup (wifi, 30% display backlight) idle power consumption is about 4.8W - my idle states never goes below C6/pc6 even running the latest 4.8 kernels. (Did the SATA power state stuff ever get fixed?)
With TLP setup, I'm able to get 8-10hrs of battery life w/o issues (I've gotten up to 13hrs if all I'm doing is editing text).
According to powertop, I can get power usage to go to over 18W on full load (100% CPU/DRAM, 100% display backlight), but under my normal setup (wifi, 30% display backlight) idle power consumption is about 4.8W - my idle states never goes below C6/pc6 even running the latest 4.8 kernels. (Did the SATA power state stuff ever get fixed?)