I recently bought a secondhand iPod shuffle 3rd generation from my local CEX. However there is an issue with the battery. I fully charged the iPod shuffle until the green light came on and took it off the wall charger. I then switched it on with a green light to tell me it’s 100% charged. However, after listening to music for 20 minutes I am greeted to a voice telling me that battery is low. I switched it off and on again and when I do that I get an amber and red light which means battery is low but I then switch it off for about 15 minutes and when I switch it back on the green light displays telling me it’s 100% charged but again after listening to music for 20 minutes I am again greeted to a voice telling me battery is low. What is going on. Does this mean the battery is dying and I’ll have to get the battery serviced. I have tried restoring and resetting the iPod shuffle but getting the same problem.