My Chevy Impala battery light comes on after I drive 15 minutes. What is the problem?

[trickydicky]

Light is never on when starting. Not sure if the alternator is the problem.

[lucas8888]

battery is just used to start the car then the alternator is used to keep it going

[mommyofandyjr02]

it could be a loose connection, you usually can get it checked out for not a lot at most car shops

[lexusry]

you need a volt meter and hook it up to the battery.it should read 13.4 to 14.5 volts.if it does not read these numbers,you have a bad alternator. 99 percent of the time for this car is a bad alternator when the battery light come on.