Default [Q] battery time

No matter how hard i try , No matter wich rom im using , no matter wich kernel i use i get same crappy battery time, Even when i browse without any brightness on my batter goes down in % quick...10 mins on time and already at 95 %... My battery must be faulty ?? :S I still got warranty on the phone if i reset to stock kdz.. But any suggestion what to do before i contact LG ? Thanks