I am currently an owner of an Ipod Touch 4th generation. I see you are having problems with your Ipod Touch/Ipad/Iphone/Ipod Classic, so I will try to find a solution to your problem.
- Do the IOS update (the one that is the latest)
- Reset All Settings: SETTINGS>GENERAL>RESET>RESET ALL SETTINGS
- Use it until it dies (automatically shuts off)
- Plug into Charge
- Leave it 1.5 hours or longer after it reaches 100% --> Undisturbed (preferably overnight)
- Give it a few days to Calibrate
This has helped me on my Ipod Touch 4th generation, running IOS 6.0.1
Hope that helps!
If none of the above solutions work, can you please respond back ASAP as I will try to find another solution to your problem (This might even help others with the same problem!)