The battery can last anywhere between 4 hours (video) to 50 hours (music). If you're looking to get more battery life, you might consider turning off the video display when playing music, and turning down the backlight when it is on. Those two recommendations alone may help you get more life out of your unit.

Since it charges on the PC, the PC has to be on or working. I believe it will also charge with a powered USB hub. It shouldn't take more than 12 hours to charge, depending on the amount of energy that remains. How long should it normally take? I would think no more than 6-8 hours, assuming that the battery was completely depleted.