What is Battery Ignition System?- Definition & Working

What is Battery Ignition System?

A battery ignition system has a 6- or 12-volt battery charged by an engine-driven generator to supply electricity, an ignition coil to increase the voltage, a device to interrupt current from the coil, a distributor to direct current to the correct cylinder, and a spark plug projecting into each cylinder.

Current goes from the battery through the primary winding of the coil, through the interrupting device, and back to the battery.

In older automobiles, the interruption of the primary current was created by breaker contacts, a switch with tungsten contacts to retard erosion. Driven at half engine speed, a breaker cam, a rotating object with a lobed surface (one lobe for each cylinder), opened and closed the points.

When the breaker contacts closed, current flowed through the primary winding of the ignition coil. In electronic ignition systems introduced in the early 1960s, the interrupting device is a reluctor, a magnetic pulse distributor that produces timed electrical signals that are amplified to control the current to the ignition coil’s primary winding. Such systems generally reduce ignition maintenance and increase engine efficiency.

The primary winding consists of a wire wound around an iron core. Above this is a secondary winding with many more turns of finer wire attached to the distributor. Current flowing through the primary winding creates a magnetic field.

When the breaker cam opens the breaker points or the reluctor delivers its signal, the circuit is broken and the current is cut off. The magnetic field collapses and induces a much higher voltage in the secondary winding, which is fed to the distributor. Inside the distributor, a moveable finger rotates at half-engine speed.

As it rotates, it touches contacts that each go to a different cylinder. The rotation is timed so that when the finger touches the contact for a particular cylinder, a high voltage has just been induced in the ignition coil secondary winding and the piston has almost reached the top of the compression stroke. A high voltage is thus impressed across the spark plug gap.

The spark plug consists of a center electrode embedded in an insulating ceramic. Around the outside is a threaded metal shell that screws into a hole in the top of the cylinder. A ground electrode extends from the cup over the end of the center electrode. There is a small gap of 0.015-0.040 inches (0.038-0.102 cm) between the two electrodes.

At around 8,000 volts, a spark jumps across the gap and ignites the air-fuel mixture. A centrifugal feed allows the spark to ignite earlier at high engine speeds; A vacuum advance allows it to fire earlier at small throttle openings above idle.

Parts of Battery Ignition System

The main components of the Battery Ignition system are listed below:

  • Ignition switch
  • Battery
  • Ignition coil
  • Ballast resistor
  • Contact breaker
  • Distributor
  • Capacitor
  • Spark Plug

Ignition Switch

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

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

Battery Ignition System


The battery is provided for 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 use widely, one is lead-acid battery and another one is the alkaline battery. Although there are Zinc Acid Battery and Lithium-Ion Battery is used in modern vehicles.

Ignition coil

It is the main junction or you can say the main part of the Battery Ignition System. The main purpose of it is to step up battery voltage so that it is sufficient for generating the spark.

It is working as a step-up transformer, and have two winds, one is primary which has a lesser turn, and the other one is secondary which has a higher number of turns.

Ballast resistor

This is used to limit the current in the ignition circuit and generally made 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 the spark in each spark plug at the correct sequence.

There are two types of distributors.

  • Carbon Brush Type: It is consisting of Carbon Brush which is 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. that’s why 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 it supplied the additional current 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 the Battery Ignition system. Here the actual Spark is generated for the combustion of Fuel or Charge. If there is more than one spark plug that exists then each one is connected separately with the distributor and gives the spark in the sequence.

Working of Battery Ignition System:

In Battery Ignition System, when the Ignition Switch is turned on then the current will flow to the primary circuit through the ballast register, primary winding, and contact breaker

The flowing current induced a magnetic field around the primary winding, the more current we supply the more magnetic field will generate. At a certain time, the contact breaker opens the current is flowing through the primary winding and falls. This sudden fall of current generates a 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 charged fully then it starts delivering the current towards the battery, due to this reverse flowing 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.

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 its starts rotating then at a certain stage it opens the contact breaker point which allows the high voltage current to be 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 a Battery Ignition System:

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

Disadvantages of Battery Ignition System:

  • Efficiency decreased with a reduction in spark intensity.
  • Occupies more space.
  • Efficiency decreased with a reduction in spark intensity.
  • Need periodic maintenance is needed for the Battery only.

Applications of Battery Ignition System:

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


What is a battery ignition system?

A battery ignition system has a 6- or 12-volt battery charged by an engine-driven generator to supply electricity, an ignition coil to increase the voltage, a device to interrupt current from the coil, a distributor to direct current to the correct cylinder, and a spark plug projecting into each cylinder.

What are the advantages of battery ignition?

The initial cost of the battery ignition system is very low. Battery ignition gives a good spark at starting and at the low speed of the engine. The driving of a high-speed engine is simpler than in the case of a magneto system. The periodical maintenance required is negligible except for the battery.

What are the main components of a battery ignition system?

The basic components in the ignition system are a storage battery, an induction coil, a device to produce timed high-voltage discharges from the induction coil, a distributor, and a set of spark plugs.

What is the difference between a magnet and a battery ignition system?

A magneto ignition system uses its own electric generator instead of a battery to derive power for an electric spark. In a magneto ignition system, all the parts of the battery ignition system are replaced except the spark plug.