Clean both battery cables and check the connections on the alternator. If it continues, go to auto zone and have the alternator checked.
What does it mean when the airbag light and battery light on 1999 Ford Escort flashes?
Possible alternator problem
More than likely your alternator is getting ready to go out.
my battery is still on after changing battery and altnator
Loose connection? Bad ground? Weak battery?
Normally it means the alternator is failing.
If the light is still on then the problem was not the battery but was instead the alternator which is more than likely defective.
either alternator or wrong size battery
Sounds like the brushes are worn down in the alternator.
Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alt belt.
poor charge or intermitant charge from the alternator, also check condition of the alternator belt
Probably your battery cable or cables are loose on one end or the other.