You're Charging It Wrong
After 27 overheating incidents, six fires and four customers with minor burns, Apple Japan has offered replacements for first-generation iPod nano mp3 players that overheat while charging. The Japanese government has been highly critical of the company for its delay in confirming and reporting these and 34 other “non-serious” cases of overheating. Apple reports that the defect can be traced to a specific battery supplier.