My iPod Only Works When It's Chargingby Robert Schrader
Before using your iPod portable MP3 player you must charge its battery. You can do this through your computer or using a standard wall outlet. If your iPod works only when it's plugged in and charging, several possible explanations exist.
The iPod Battery
Like your laptop, cell phone and other electronic devices, your iPod is equipped with a rechargeable battery, one you replenish by plugging it into a power source. iPod batteries are designed to withstand hundreds of charges, although they eventually stop being able to accommodate new charge. If your iPod works only when you're charging it and it's an older device, your battery may simply have worn out.
Computer vs. Wall Charging
It's possible to charge your iPod either through your computer or using a wall outlet. Both options make use of the iPod's USB cable: the cord plugs directly into your computer or into an adapter that plugs into the wall. If you've been charging your iPod only through an outlet, try plugging it into your computer---which will result in its docking and synchronizing with iTunes---to see if any other errors arise. If they do, a software rather than a hardware problem may be to blame.
Your iPod may be damaged. Water damage can affect the function of your battery. Whether your drop it in a puddle or toilet or leave it in the bathroom while taking a shower, exposing your iPod to water or even excess humidity can affect its battery function. Your iPod can also be damaged if you drop it or it is exposed to an electrical surge while plugged in.
Repair or Replacement
If a new iPod isn't in your budget or doesn't seem appropriate given the age of your device, your best option is to turn your device over to Apple for repair, whether in person---at an Apple store---or by calling customer service and obtaining the address of your nearest service center. Unfortunately, even if your iPod is within its warranty period---one year by default, provided you haven't damaged or altered your device---repairing or replacing the battery isn't a covered service, so you'll have to pay out of pocket.