The battery warning light is an indication that your vehicle's charging system is not working properly. There are a few different things that can cause the battery warning light to come on, and it is important to diagnose the problem as soon as possible. The most common cause of the battery warning light coming on is a faulty alternator. If your alternator is not working properly, it will not be able to charge your battery correctly and the battery will eventually die. Another common cause of the battery warning light coming on is a loose or damaged connection between the battery and the Alternator. If you have a loose or damaged connection, it can cause an electrical current leak which will drain your battery over time. Finally, if your vehicle has been sitting for a long period of time without being used, the battery may simply be old and need to be replaced. No matter what the cause of your battery warning light, it is important to have it checked out by a qualified mechanic as soon as possible so that you can avoid being stranded with a dead battery.