I have a portable dvd player and it came with this battery and I didn't know if you had to attach it in order to use it so I attached it and there was this little DC 9V plug cord and a DC 9V input thing for it I guess, but the dvd player has a DC 9V input thing to and I have a seperate cord for the player, so do I have to leave both in for it to charge? I took a picture if you dont know what I mean, please help me Thanks.