Default [Q] Xperia z battery draining

Hellow I'm a happy owner of the xperia z for 10 days, but I'm facing fast battery drain when using the phone. When Im just browsing the phone, battery goes down 1% percent every 3~4 minutes... When gaming battery drops 2-3 % every 5 minutes. I need some help, I didnt charge the phone the first time for 8 hours, but i read it is not necessary. I'm rooted, 4.3 jb, doom kernel v21. I have deleted some of the bloatware and i don't have WiFi and data on all the time. Also media server sometimes goes up to 21% in battery usage.