570E Battery problems

[Raere]

Yes, it's me again. The one with the video problems. Now that the video is working, I have one more pet peeve with the machine - the battery. I read somewhere that the 600 series had some battery problems, but it could be fixed with a BIOS downgrade. My battery runs to around 80%, then suddenly drops to 0%, and shuts off. However, if I turn it back on, it continues to run for another half hour, with the battery saying 0%, and the LED flashing amber. I bought another battery to hopefully solve the problem, but it does the same thing. I've since reset the BIOS and reformatted to no avail. Any way I can get my machine to actually read the battery's real life?