iPod shuffle 2nd generation charging query

When I put my iPod shuffle on charge, it shows a non-blinking green light telling me it’s fully charged but when I take it off charge, I turn it on and it blinks red and turns off telling me it’s dead. I left it to charge through my normal plug and charging dock but it blinks orange twice then stops telling me that it is used as an external disk. I change the charger completely and charges it through the “shavers only” socket in the bathroom and that’s when it shows the non-blinking green light. What do I do here and how do I fix it?