MacBook Not Charging, but it says that it is...

I have two batteries for my MacBook and I just decided to start using the second one. When I put in the battery, it has NO CHARGE. So, I start it up with wall power, and go to Battery information. It says
Cycle Count "19"
Charge Remaining "0"
Fully Charged "No"
Charging "Yes"
Full charge Capacity "5039"
Condition "Normal"

Any ideas? I am pretty confused since it had no problem charging the other battery.
It might be worth pointing out that I have a White MacBook and a white battery, but the one not charging is a Black battery (spare). Now Apple said they are interchangeable, so...IDK..


*NOTE*
I have tried the battery in two different MacBooks. Neither will charge it, yet both say it is charging? Its only 19 cycles!! What gives? One MB was on Leopard and one was on S Leopard. Hmmm....


Any help is appreciated. Thanks!

Either your black battery is not compatible or it's defective. Did you buy it from Apple direct or from another reseller? There are batteries that are sold as Apple compatible that turn out to be inferior or won't work at all.

Regards.