christ some people where are thick.
the battery lasts for 40 hours. who the fuck will play for 40 hours straight? if you do, you have problems.
and the fact that it gives you a warning when its got 4 hours to go is lots. take a break every now and then, and you will be fine.
and if you to stubborn to do that, get a usb hub that looks good (yes, they are made), and use that.