The amount of time it takes for a light to drain a car battery depends on various factors, including the type of light bulb, its wattage, the condition of the battery, and the overall electrical system of the vehicle. Generally, a standard car battery with a full charge can typically power a 50-watt bulb for approximately 20 hours before being completely drained. However, it's important to note that continuously draining a car battery can significantly reduce its overall lifespan and performance.
It's advisable to avoid leaving lights on when the engine is off for an extended period to prevent the battery from dying. Most vehicles have systems in place to prevent complete battery drainage, such as automatic shutoff timers for interior lights or warning chimes. Nevertheless, it's still wise to be cautious and avoid unnecessary drain on the battery. If you do happen to leave a light on and notice that your battery is weak, it's best to recharge or jump-start it as soon as possible to avoid potential damage.