Battery won't work

I'm trying to make a New Battery to work in my macbook air, but it doesn't charge....

I tried everthing.. resetting the SMC, unplug-plug... nothing works... the light from the charger remains green al the time. Just once was red for a few hours, but I started the computer, and the battery indicator said, battery not charging... When I unplug the charger, the computer shuts down inmediately. My old battery still works (it lasts only 30 min, but it works).

Any ideas?

Thks.