A variety of things could prevent the iPod from being charged by your computer. I found some useful information about charging your iPod battery using your computer:
Unexpected Charging Behavior
There are certain situations where certain iPods may display behavior in which it looks like the battery isn't charging when it actually is. Or you may think your iPod is charging but it is not:
- iPod will stop charging if the computer or portable computer it's connected to goes to sleep. Turn sleep off and make sure the portable is plugged into power.
- If the battery is fully discharged on earlier iPod classic models, you may have to wait up to ten minutes before your computer will recognize it. Click here for additional information.
- If you use Windows 2000, the iPod may stop charging after it syncs.
Using Your Computer
If you want to charge your iPod using your computer, make sure that your computer is turned on, it isn't sleeping (refer to the computer's manual to find out how to turn sleep off), and that the USB or FireWire port you connect your iPod to provides power. If you use USB, connect your iPod to a high-powered port using the USB cable that came with your iPod (or an Apple-branded cable). High-powered USB ports are typically found on the computer itself—not on your keyboard, which is low-powered.
Note: If using a portable computer, make sure it is plugged into power and that the lid or display is open because if the lid is closed the computer may go into either standby, sleep, or hibernation mode and iPod will not charge.
You can find the full article here:
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