Windows 7 Windows 7 Laptop Battery Issues

[f40player]

I just installed windows 7 today. I used to get maybe an hr of battery life on vista, when i got windows 7 now i might get only 20 minutes. It has a red X next to the battery icon and says i should "consider replacing the battery". This warning X though appears and dissappears. It will always appear once i plug the charger in. Is it possible there is a driver conflict or something as i doubt my battery life could just die like that after an OS install. i run a dv6000 series