battery low 701CS

["Manuel VILLARET" <Barbaro@club-internet.fr>]

Hv following problem with my 701 CS battery.though the battery indicator
(Fn+F2)indicates I still have an hour or so to go,the computer turns
suddenly off without even letting me save my work.The total working time I
have is approx 1 hour before this occurs
Is this a problem of "memory effect" or is it just that my battery needs
replacement? 

thanks 
Manuel
thinkpad 701 CS
486 DX 4
16 RAM