you may want to consider downgrading to iOS 6.0.1 to fix this problem before apple stops signing 6.0.1. This problem is recurrent in iOS 6.1
As an Apple Developer, i can assist you in fixing this problem. Search the web for the iPod4,1_6.0.1_10A523_restore.ipsw
Download it then save it to the desktop.
Open iTunes and connect the device. You can then go to the device summary and [on mac hold OPTION and click update, or on PC hold Control+shift and click update] this should allow you to manually select an ipsw to update to. Search for and click on the iOS 6.0.1 ipsw and proceed to update which will actualy downgrade your device to the pointed software, consequently, fixing your battery bug. You may also consider draining the battery fully and then recharging it all the way, but UNPLUG it when the device is fully charged. Overcharging has potentially deadly effects on the battery of the device.
if you have any questions on my reply or future issues, feel free to send me a message at email@example.com, and i will happily assist you.