What does it mean when the battery red light on the car dashboard is on?

[DonovanFitz]

The battery red light on the car dashboard is a warning to the driver to promptly check for vehicle faults. If the battery light is on before starting the vehicle, it indicates that the alternator or battery is not charging. Possible causes for the dashboard battery light to illuminate include: 1. Battery failure, such as depleted charge or battery malfunction. The solution is to use a multimeter to test the battery voltage; if the voltage is too low, recharge it, and if the battery is faulty, replace it. 2. Loose or oxidized battery terminals causing poor contact. The solution is to clean and tighten the battery connections. 3. A loose alternator belt or tensioner pulley. The solution is to replace the belt or adjust the tensioner pulley. 4. Faulty alternator voltage regulator or excitation circuit. The solution is to troubleshoot the alternator.