I personally just disabled the power saving mode. All it does is disable your radios like wifi, gps, bluetooth and changed how your screen acts when it reaches the set threshold. I found that using widgets like facebook or twitter is the main culprit in battery draining. Since I removed those widgets, my battery now lasts me at least 12 hours with all the radios (minus bluetooth) enabled w/ my screen set to auto and a 30 second timeout.