It's certainly very important to be able to charge your iPod nano. I found a couple of useful resources that might help with getting your iPod nano back on track.
I found some information about why you may not see the charging symbol on your iPod:
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.
- When you eject iPod nano 5th generation or earlier in iTunes but leave it connected to the USB port, the battery indicator at the top of the screen may not animate when charging. If you see a lightning bolt in the battery indicator icon, iPod nano is charging. For iPod nano 6th generation or later, you will see a lighting bolt when the battery is charging.
- When you connect iPod nano to your computer using a USB hub, the battery charging indicator may appear to slow down. This is cosmetic and does not mean that iPod nano is charging more slowly.
- If you use Windows 2000, the iPod may stop charging after it syncs.
You can find the full article here:
If you are still not able to charge your iPod nano, I recommend following these steps:
Will not turn on or screen remains dark
- Connect iPod to power for at least ten minutes to ensure that the battery has enough charge to allow iPod to turn on.
- If iPod does not turn on after ten minutes, try resetting the device while it is still connected to power. Reset the iPod by holding down the Sleep/Wake button and the Volume Down button for at least eight seconds or until you see the Apple logo appear.
- If the Apple logo appears on the display, connect iPod to a computer and verify that it appears in iTunes and can play music. If iPod appears in iTunes and can play music, no further troubleshooting is needed.
- If the screen remains dark and will not turn on, then your iPod may need service.
This comes from an article about the 6th generation iPod nano, but the steps are the same for the 7th generation of the iPod nano as well:
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