From which source does a vehicle's electrical system receive its energy?

The vehicle's electrical system receives its energy primarily from the alternator. The alternator plays a crucial role in converting mechanical energy from the engine into electrical energy, which is then used to recharge the battery and power the vehicle's electrical systems while the engine is running.

While the battery stores electrical energy and provides power to start the engine and to operate electrical components when the engine isn't running, it is the alternator that keeps the system energized during operation. The starter motor is responsible for cranking the engine to start it, but it does not provide energy for the electrical system once the engine is running. Therefore, the alternator is the key component supplying the ongoing electrical energy needed for the car's functions while in operation.