Battery Ignition System: Definition, Parts, Working Principle, Applications, Advantages, and Disadvantages (Notes with PDF)

feature image of Battery Ignition System

Last Updated on March 4, 2023 by Noaman Adenwala

What is Battery Ignition System?

A battery Ignition System is used in an automobile to produce a spark by the spark plug with the help of a Battery. It is generally used in the 4-wheeler vehicle but nowadays it is also used in two-wheeler vehicles where a 6-volt or 12-volt battery supplies the current to the ignition coil.

Parts of Battery Ignition System:

The main components of Battery Ignition system are listed below:

  1. Ignition switch
  2. Battery
  3. Ignition coil
  4. Ballast resistor
  5. Contact breaker
  6. Distributor
  7. Capacitor
  8. Spark Plug
Diagram of Battery Ignition System, Learn Mechanical

Ignition Switch

It is used to turn ON or OFF the engine. One end of the switch is connected with the Primary Winding of the Ignition Coil via the Ballast Resistor, and another end is connected to the Battery.

Basically when the key is put inside it and turned the switch in ON position then the circuit is completed (Close Circuit). When moved towards the OFF position then it works as an open circuit. Nowadays, this switch is replaced by the Push Button, and this system is called a keyless system.


The battery is used to supply the initial current to the ignition system more specifically ignition coil. Generally, the voltage of the battery is 6V or 12V, or 24 V. In an automobile there are two types of Battery used widely, one is a lead-acid battery and another one is an alkaline battery. Although there are also Zinc Acid batteries and Lithium-Ion batteries used in modern vehicles.

Ignition coil

It is the main junction or you can say it is the main part of Battery Ignition System. The main purpose of it is to step up battery voltage so that it is sufficient to generate the spark. It works as a step-up transformer, and have two winds, one is primary which have a lesser turn, and the other one is secondary which have higher number of turn.

Ballast resistor

This is used to limit the current in the ignition circuit and generally made up of Iron. It is placed in series between the Ignition Switch and Ignition Coil. However, it is used in old automobile vehicles.

Contact Breaker

The contact breaker is an electrical switch which is regulated by the cam and when the breaker is open, current flows through the condenser and charges it.


It is used in the multi-cylinder engine, and its purpose is to regulate spark in each spark plug in the correct sequence.

There are two types of distributors.

  • Carbon Brush Type
  • Gap Type

Carbon Brush Type:

It consists of Carbon Brush which slides over the metallic section embedded in the distributor cap.

Gap Type:

In this type, the rotor arm is passed through the metallic section of the distributor cap but it does not touch the surface of the distributor cap. Hence it is called Gap Type Distributor.


A capacitor is a storing device where electrical energy is stored. It is fitted parallel to the contact breaker, when the current drops, then the additional current is supplied so that the spark is produced. It is made of two metal plates separated by air or any other insulating material.

Spark Plug

Spark Plug is another important part of Battery Ignition system. Here the actual Spark is generated for the combustion of Fuel or Charge. If there is more then one spark plug then each one is connected separately with the distributor and gives the spark in the same sequence.

Working Principle of Battery Ignition System

In Battery Ignition System, when the Ignition Switch is turned on, the current will flow to the primary circuit through ballast register, primary winding and contact breaker The flowing current induce a magnetic field around the primary winding, the more current we supply the more magnetic filed will generate. At a certain time, the contact breaker opens the circuit through the primary winding and fall. This sudden fall of current generates very high voltage around 300 V in the primary winding section. Due to this immense amount of voltage the capacitor comes into the charging state. When the capacitor is fully charged then it starts delivering the current towards the battery. Due to this reverse flow of the current and already induced magnetic field in the primary winding, a very high voltage of 15000 V to 30000 V is generated in the secondary winding.

Source :

This high voltage current is then transferred to the distributor via high tension cable, where already a rotor rotates inside the distributor cap and has metallic segments embedded on it. So when it starts rotating then at a certain stage it opens the contact breaker point which allows the high voltage current to transferred to the spark plugs through the metallic segments. So when the high voltage current reaches the spark plug then its generates a high intensity of spark inside the engine cylinder, which allows the combustion fuel to burn.

Advantages of Battery Ignition System

These are the following advantages of Battery Ignition System:

  • The intensity of spark is high.
  • It can also provide a high concentration of spark even at low engine speed or at the start of Engine.
  • The maintenance of this ignition system is very less compared to others.

Disadvantages of Battery Ignition System

The disadvantages are:

  • Efficiency decreases with a reduction in spark intensity.
  • Occupies more space.
  • Periodic maintenance is needed for Battery only.

Applications of Battery Ignition System

Battery Ignition System is used in Automobiles (Car, Bus, Truck even in the Bike) to produce the Spark so that Combustion fuel can be burned.

More Resources:


  • Diagram of the Battery Ignition System is made by Saubhik Roy- Design team LM.
  • The feature image is designed by the Author.


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