Battery issues

[Xmetal]

I'm having problems with one of the batteries in my 350D, i'm using the Canon battery grip and it's all working except one of the batteries isn't charging properly - if I put it on the charger the red light comes on (like normal) then it turns off after 5mins, if I put the other battery in the charger it charges normally for an hour or more then the red light changes to green to say it's finished.

Do I have a paper weight on my hands?

 

[markc]

Are you sure that you are running the one battery down enough so that the camera starts using the other? Try switching their positions in the camera. I can't remember if it actually works that way or if they drain at the same time, but I seem to remember on my 10D one will drain first.