About the iPod classic Battery
iPod classic has an internal, non-user-replaceable battery. For best results, the first time
you use iPod classic, let it charge for about four hours or until the battery icon in the
status area of the display shows that the battery is fully charged. If iPod classic isn’t
used for a while, the battery might need to be charged.
The iPod classic battery is 80-percent charged in about two hours and fully charged in
about four hours. If you charge iPod classic while adding files, playing music, watching
videos, or viewing a slideshow, charging might take longer.