Dell Latitude CPi (PPL) battery issue

I was just wondering if someone could help me solve a battery problem with my laptop. I just replaced the existing dead Dell Li-ion 3800mAh battery with a more powerful 4460mAh battery. The battery is now at full charge! All the green led lights on the new battery are working and the power scheme on my laptop shows the new battery at full charge. The problem is when I disconnect the ac power source or try to start it using only a battery charge nothing happens. Is there something I need to do to correct this problem. The computer obviously recognizes the new battery or it wouldn't show it as being charged in the power scheme window. I am running windows xp if that makes a difference. Any suggestions would be welcome.

 

I'm guessing it's an off-brand generic battery you're using.

 

You're right! The new one is made by Panasonic but it was supposed to be compatible with the original battery type 75UYF made by Dell. Could that be the problem? I would think so if the battery didn't charge at all or it wasn't even being recognized by the computer. But so far the new one seems to be working fine except that it doesn't switch to dc power once the power cord is disconnected. Has anyone else had problems when switching from a Dell battery to a generic one in a Latitude notebook?