ics can also last 3days~
well , in another thread there are discuss about an ICS bug cause severe battery drain, I myself just got the same problem and followed the instructions ( which is: turn off touch sound, lock sound and touch vibration feedback, btw I'm not sure if I spell these items correct because I'm using Chinese),then My little Ray's battery just get enough power to last for 3 days' usage.
I got about 5 calls per day, almost no SMS but read E-book for 1 and a half hour and listen to music at the same time.