To add to this comment, you're probably not gonna be able to change the battery. It's extremely difficult and time consuming. Here's an Ifixit guide if you actually want, or need to change or repair one - https://www.ifixit.com/Guide/iPod+Nano+3rd+Generation+Battery+Replacement/749. But there's a seller on eBay who I bought my 2g Nano from that came without a black spot and still works perfectly a year later, if you want to buy a 3g Nano your best bet is him -https://www.ifixit.com/Guide/iPod+Nano+3rd+Generation+Battery+Replacement/749 . Glad I could help!