Replying to Ipod Battery Problems

Alright, I dont have a problem with my Ipod Battery, but I do have an assignmnet where I must report a technical problem and provide possible solutions. SO now this is where i need your help. If you have ever had a problem with your Ipod battery, it doesnt matter what Model of the Ipod I would like you to tell your story of what was wrong and how apple/you fixed it, if you were able to fix it. Also I see you can buy replacements for the battery at Best Buy/Future shop and such, has anyone ever tired that and if so how did it go?? Thanks