Have a look at this, copied from iPod nano (6th generation): Hardware troubleshooting
- Learn how to conserve battery life.
- Learn how pressing the Sleep/Wake button affects battery life.
- Ensure that the latest software is installed on the iPod.
- When charging, use the cable that came with iPod nano (6th generation) and leave the device connected until it is fully charged.
- Note: If you are charging using your computer, don't connect iPod nano (6th generation) to your keyboard. Also, the computer must be turned on and not in sleep or standby mode. If iPod nano (6th generation) is connected to a computer that's not turned on or is in sleep or standby mode, the iPod nano (6th generation) battery may drain.
- When you are done using the iPod, verify that:
- Dimming the screen is another way to extend battery life on iPod nano. Go to Settings > Brightness and restore the brightness to the default, or drag the slider to the left to lower the default screen brightness.
- Playing tracks with EQ requires your iPod processor to consume more energy than playing tracks without EQ, since the EQ information is not encoded in the song. To prolong battery life, turn EQ off if you don’t use it. Note, however, that if you’ve added EQ to tracks in iTunes, you’ll need to set EQ to “flat” to have the effect of “off,” because iPod keeps your iTunes settings intact.
- Try restoring iPod nano (6th generation) by connecting it to iTunes and clicking restore.
- Test your battery life by following the steps in this article.
- Digital music playback uses battery power efficiently, allowing iPod nano to play music for up to 24 hours. Other features, such as FM radio, consume more power.
- You cannot charge iPod nano (6th generation) with a FireWire power adapter or FireWire-based car charger.
About the battery
iPod nano has an internal, non–user-replaceable battery. For best results, the first time you use iPod nano, let it charge for about three hours or until the battery icon shows that the battery is fully charged.
The iPod nano battery is 80-percent charged in about one and a half hours, and fully charged in about three hours. If you charge iPod nano while adding files, playing music, listening to the radio, or viewing a slideshow, it might take longer.
Charging the battery
You can charge the iPod nano battery by connecting iPod nano to your computer, or by using the Apple USB Adapter (available separately).
Charge the battery using your computer:
Connect iPod nano to a USB 2.0 port on your computer. The computer must be turned on and mmnot in sleep.
Important: If a “Charging, Please Wait” or “Connect to Power” message appears on the iPod nano screen, the battery needs to be charged before iPod nano can communicate with your computer. See “If iPod nano displays a “Connect to Power” message” on page 53.
copied from page 14 iPod_nano_6thgen_User_Guide