@BorisHristov - It might help if you generate battery and sleep study report and share your results. You can look at those numbers and see at what times the drains occur and correlate that with what you might have been doing. Some have seen that they actually lose charge while in Hibernate, which would not be good. Throw the following two commands into a .bat file, save on the desktop, and then right click/run as admin. It will generate two html files.
powercfg /batteryreport /output "C:\Users\*boris*\Desktop\battery.html" /duration 7
powercfg /sleepstudy /output "C:\Users\*boris*\Desktop\sleep.html" /duration 7
Note: Max duration can be 14 days.
I have nothing turned off in terms of background notifications, etc. Wi-Fi is on during sleep. Why? Because if you turn all that off then you might as well turn off connected standby and use hibernate. Or even better, disable hibernate, safe disk space and just shutdown
Anyway, my battery drain during sleep is about 1.5 % per hour, but I had to use an older display driver to achieve that. Using the latest or beta, and I'm back at the 4% that Zkyevolved sees (and as well as many others from different forums/sites). One guy on answers.microsoft claims that MS is aware of the issue and is working on it. I hope so.
I'm getting about 5 to 6 hours of active use before having to charge. The battery life estimates from the battery report show something similar. Keep in mind that those are estimates. The 5 to 6 is for average everyday stuff (browsing, Office 365, etc). Video conferencing with Skype Video will chew up battery much faster. You can get an idea of how much power an app might use by running a battery report, noting the time, then running the application, and then generating another battery report when done. The built in Skype app consumes a lot of power, but the people on the other end tell me the video quality is spectacular. So perhaps that app is worth it ...
One other thing that I did was to cap the max CPU while on battery, by setting it to 95%. This keeps the CPU from jumping into turbo all the time and maxes at 2.3 GHz (i5 model here). However, not sure if that helps to save any significant amount of power while using the battery and just may revert it back to the default setting. I really won't know for a couple more days of use and checking the numbers in the reports.
The 9 hours claimed by Microsoft is just a marketing gimmick. The scenario (as defined by the fine print *) doesn't represent and realistic use case scenario. You're not going to setup a video to loop and stare at your screen for 9 hours. It's unfortunate that people don't read the fine print there. Many buy the device thinking they are going to get 9 hours of general everyday use - you won't. As for those here claiming battery life LONGER than 9 hours, well, I have very hard time believing them. Perhaps they could share some battery report data to support those claims, or give me money and I'll believe anything they have to say. Until then, I'll just ignore them.
