Bad battery life is a common problem after jail breaking or updating phone software. One of the first things you should do is to calibrate the battery. I noticed my battery life decreased after jail breaking. I did a calibration last night and I'm at 88% at 4:22pm. I have not charged the phone since morning. 1. Let the battery drain completely until the phone shuts itself off. 2. Let the phone stay dead for at least 5 hours. 3. Fully charge the phone without interruption. I recommend manually shutting off the phone while its plugged in for fastest charge. Do not unplug the phone at any point during the charge process. 4. Hard reboot the phone by simultaneously holding HOME and POWER buttons until the apple logo comes up.