I use 2x battery on my LTEVO. It is more of a battery percentage widget in the notification bar more than actually saving battery life. I get between 10 and 20 hours of life in my day to day. 10 hours when I work because working in a slow traffic sprint store ='s lots of "studying"? With normal day to day , checking emails, texting, facebook, and constantly taking pictures and video; I'm getting easily around 15-20. Overall happy coming from my Epic 4G Touch battery that seemed to drain to 50% while I'm laying in bed checking emails and texts for about 30 minutes.