Is there anything you need to do / configure, as I am not getting that sort of battery out of my X1 Carbon running Mint. (I realize I usually leave bluetooth on, and the screen at mid to high brightness and have about 20-30 tabs open in firefox but I would still be lucky to get 5 hours out of it.)
On my machine mentioned upthread, I have a third party SSD installed which apparently fools the firmware into disabling SATA link power management. Powertop will tell you about most goofs like that.
Beyond that, run a current kernel (my measurements are on Fedora's 4.8.12 kernel). Also recognize that recent Intel SoCs have gotten a lot better at idle power draw. The "X1 Carbon" brand started with (I think) Ivy Bridge boards which obviously aren't going to perform like this.
Current/modern kernel (I run Arch), disable unneeded radios (bluetooth and lte for me), slightly lower (but still nice) brigtness on the screen and agressive tuning by powertop..
