Why does my ipot keep on turning off?

after a bad battery took on my ipod i had to replace it after the replacement the ipod just lived for hours and i put it to charged and the charching logo diplayes, but it didnt charged, and now when i turn in on it shuts down, when i conect it to the charching doc it doesnt stay on, what that means that ipod isnt chargind, should i strive for a bad souldering?

Thank you, also, is an ipod touch 1 gen 8gb