Ford Exployer-2000

I had my alternator replaced 1 year ago and the battery light is on some of the time starting about 2 days ago.  Today it seemed to come on 4 maybe 5 times throughout the day for 2 or 3 seconds each time.  Should I be concerned? I have had the motor replace 2 years ago.  The car has about 248,000 miles on it.