I posted earlier in this forum about terrible battery life. So what I did was this, twice I let my phone run empty. And I mean empty to the point of taking he battery out and turning it on and it would shut off right after he reboot screen. Do that until it won't turn on anymore. Charge it for 8 hours unplugged (at least) and watch the battery life improve.
Seriously, I had my phone on with moderate use (I have 2 Twitter clients, 6 Gmail and Corporate mail accounts, 2 Facebook accounts, Instagram and G+) and after 2hrs 33mins I was at 84%. By almost 5 hours I was at 56%. By 7 hours it dropped a lot down to 33%. And that was with full brightness, however, I was using Wifi and when this phone searches for signal it KILLS the battery.
Good luck, but I would HIGHLY recommend recalibrating your battery like in suggested at least twice. And try not to leave it plugged in all day the more you use the battery the better its memory and usage lasts.
Sent from my Galaxy Nexus using Android Central Forums