May I suggest you do Ye Olde Method I used on my Gen3 and also on my Green Opus? Check the disk! You can find the program under preferences for the unit (rightclick the unit icon, preferences, utilities), or on Disk Utility if you're on OS X.
Also, for future memory: if you want to recharge without stopping reading, go into screensaving mode, plug the usb cable in, press the power button, read. I do it with my iPod charger and also one of those external batteries for emergencies (the rechargeable ones; very handy).