If your battery light is on, it means that your battery is not being charged. There are a few things you can do to reset the light:
1. Check your battery terminals to make sure they are clean and tight.
2. Check the charging system by starting the engine and measuring the voltage at the battery with a voltmeter. The voltage should be between 13.5 and 14.5 volts.
3. If the charging system is working properly, then check for a blown fuse or bad relay in the electrical system.
4. If everything looks good, then take your car to a mechanic to have them check the alternator and starter