Can a car run without a battery and alternator? [with Pdf]

Battery and alternator are among the vital components of any vehicle but did you think that ‘can car run without battery and alternator?’ The same question was strike in my mind when I was studying about the functions of these two parts. Therefore I did a small search on the web and in books and I got the following results that I have shared with you.

The car can’t run without a battery and alternator as the battery plays a vital role in starting the engine while the alternator supplies power to the components of the car which are necessary to continue running of the car.

Can a car run without a battery and alternator?

Now before moving towards our question let’s discuss briefly the functions of battery and alternator in automobiles.

What is the function of battery in automobile?

The automobile battery has the following important functions,

1) Starting of the vehicle:- It is the major function of the car which makes it a prior component in the vehicle. The battery supplies power to the following operations to start the engine.

a) To starter motor: Cranking is the important operation while starting of the engine that is done by the starter motor. Hence by supplying power to the starter motor the battery helps to achieve the cranking of the engine.

b) To ignition system:- Generation of spark starts the combustion process in the cylinder of the engine. The battery provides an electrical supply to the ignition coil so that the spark plug is able to generate the spark for the combustion of fuel.

In this way, the battery helps for starting the engine.

2) Supplies power to the car accessories:– The battery also supplies power to the accessories like headlights, wipers, power windows, heated seats, air heaters, etc.

What is function of alternator in automobiles?

The alternator has the following functions in vehicles.

1) Provides power for the spark generation:- After the engine gets started the alternator starts supplying electrical power to the ignition system for the generation of spark.

2) Provides power to the car accessories:- the alternator provides power to the various accessories of the engine like headlights, fuel pumps, windscreen wipers, power steering, etc.

3) Battery charging:- Charging of the battery is also the main function of an alternator as the battery performs various important functions in the working of the engine. The battery gets charged by alternator through voltage regulator that controls the rate of electric current and also helps to avoid overcharging.

Can a car run without a battery and alternator?

Without a battery and alternator, it is not possible to run the engine. Following are the reasons that will clear our doubt that, Why car can’t run without a battery and alternator.

1) Cranking is not possible: If the battery is removed then the starting motor will never get power for the cranking of engines. Therefore without cracking it is not possible to start the engine.

2) Spark generation is not possible: The battery and alternator provide electric power to the ignition system to generate the spark necessary for ignition. Therefore without a battery and alternator, it is not possible to operate a spark plug.

Even if you try to push-start the vehicle then also it will not start the engine because of the absence of an alternator.

Therefore for the operation of the engine, the battery and alternator are the important components.


Therefore it is not possible that your car will run without a battery and alternator. Hence the battery and alternator are essential components required to run the car engine.

Pratik is a Graduated Mechanical engineer. He enjoys sharing the engineering knowledge learned by him with people.

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