My battery warning light started coming on when first starting 2003 Z4. After a short time the light would go out. Since its about 7 years old I decided it was time to replace the battery. So I had the battery replaced at Sears. After start up to take it home the warning light didn't come home. Now, however, the light has returned but goes out after driving a short distance. Can anyone provide any info on this problem?

Thanks
Bill2.5i Toledo Blue, Beige Leather, Black Top, Pre. Pack, Auto. Wood Trim- The First State