External Battery

[asctony]

I have a 3g with OS 3.0 and JB. I have an external battery Capacity 1900mAh that plugs into the bottom of the phone. On the external battery it shows 4 lights to indicate a full charge. I know it is fully charged. However, when I plug the external charger into the phone, it does not charge the phone or show external charging. When I first plugged in the external battery to the phone it did charge the phone immediately. Have no idea of what is wrong.

Any ideas? Thanks in advance.