Understanding the working of Battery ignition system

Just like other types of the ignition system, the battery tends to be one of the most used ones in automotive applications. It produces spark with the spark plug and aid of battery as it typically used in the 4-wheeler vehicle but serves better nowadays on a two-wheeler vehicle. 6-volt or 12-volt battery is used on these vehicles to supply current to the ignition coil.

Today we’ll be looking at the definition, function, components, diagram, and working principle of the battery ignition system. we’ll also see the advantages and disadvantages of the device.

battery ignition system

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Battery ignition system definition

A battery ignition system is a type of ignition system used in a spark-ignition engine for powering the spark plug so that spark can be generated to burn the air-fuel mixture in the combustion chamber. The ignition system powered by a 6- or 12-volt battery charged by the engine-driven generator (alternator). This battery supplies electricity to the ignition system, thus, it’s named battery ignition system.

These types of an ignition system are commonly used in light commercial vehicles, buses, trucks as well as trucks. Its function is to produce a spark so that fuel can be burned.

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Components of battery ignition system

Below are the components of battery ignition system in their various applications:


The battery used in this system is the rechargeable lead-acid battery that stores electrical energy. The ignition system is powered by the battery which supplies current to it as soon as the engine is running.

Ballast resistor:

The ballast resistor is a component in the battery ignition system that is used to control the current that passes through the primary winding. It’s made of iron which has a property to increase electrical resistance rapidly by an increase in temperature to some extent. The additional resistance resists the flowing current that controls the temperature of the ignition coil. This helps to maintain the temperature under the prolonged condition and it’s connected in series with primary winding to regulate the current in the primary winding.


The ammeter is used for measuring the current in the system.

Ignition switch:

The ignition switch in all ignition systems used for switching on and off the system.

Ignition coil:

An ignition coil is used for changing the voltage stage in the system, that’s from low o high. It is also used for the generation of spark in the spark plug. The component consists of a magnetic core or soft wire and two electrical winding known as the primary and secondary winding.

The primary winding has 200-300 turns as the current flowing through it creates a magnetic field. Whereas, the secondary winding has 21000 turns of 40-gauge wire. It’s insulated so that high voltage can withstand.

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Contact breaker:

The contact breaker helps to add and break the primary circuit to the ignition coil. That’s. it allows current flow in the ignition coil when it’s closed and stops flows when it’s open.


The capacitor is just like the normal electric capacitor. Typically, it stores electrical energy in an electric field. In the component, two metal plates are separated from each other through the air. It’s made of insulating material. The function of the capacitor in the system is to prevent the arc from across the breaker point. The absence of a capacitor in the system will make induce voltage to cause an arc across the breaker point. This might be very dangerous.


Distributors are of two types; brush type and gap type. It also plays an important role in the system as it provides ignition pulses to the individual spark plug in sequence at the appropriate time.

Spark plug:

The spark plug is the electrical device that creates the spark that ignites the fuel-air mixture so that the explosion can occur.

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Battery ignition system diagram:

diagram of battery ignition system

Working principle:

The working of the battery ignition system is much similar to other types of ignition systems. It’s much easy to under as it works with a 6- or 12-volt battery that is charged by the engine-driven generator (alternator). The ignition coil in the system increases the voltage and a device to interrupt current from the coil. Distributors direct current to the correct cylinder, while the spark plug project the current into each cylinder. Well, all these have been mentioned above.

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The current move from the battery through the primary winding of the coil, to the interrupting device and then return to the battery. Current interruption occurs in older automobiles through the breaker point, which is a switch with tungsten contacts to retard erosion. The rotation of the cam lobes open and close these points, causing current to flow through the primary winding of the ignition coil when the breaker point is closed. In newer automobiles that use electronic ignition systems replaced the breaker point with a reluctor. It’s a magnetic pulse distributor that produces timed electric signals that control the current to the primary winding of the ignition coil. You can read about the electronic ignition system below:


Watch video to understand better:

The primary winding is made of wire coiled around an iron core and the secondary winding over it is of many more turns of finer wire joined to the distributor. As the current flow through the primary winding, the magnetic field is created. The breaker cam opens the breaker points or the reluctor delivers its signal, causing the circuit to be broken and stopped. The magnetic field then collapses, inducing the secondary winding with a higher voltage that is directed to the distributor.

In the distributor, there is a moving finger that rotates half the engine speed. This rotation touches contact with each of the contacts for a particular cylinder, causing a high voltage to be induced in the secondary winding of the ignition coil. At that same time, the piston is about to reach the top of the compression stroke. And a high voltage is impressed across the spark plug gap.

The spark plug contains a center electrode with an insulating ceramic around it. the outer portion is a threaded metal shell that is screwed into the cylinder top hole. The ground electrode extends from the shell over the end of the center electrode. The two electrodes have a small gap of .015–.040 in. (.038–.102 cm). A volt of about 8,000 sparks jumps the gap and ignites the fuel-air mixture.

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Advantages and disadvantages of battery ignition system


Below are the benefits of battery ignition system in its various applications:

  • Have good spark intensity.
  • Required less maintenance like the other types of the ignition system.
  • Offers a high concentration of spark even at low engine speed or first starts.
  • Produce more power output.
  • Fuel efficiency is good.
  • No moving part in the system.
  • Better combustion as it burns more than 90 percent of the fuel, unlike other types of ignition systems that could burn only 70 to 75 percent of the fuel-air mixture.

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Despite the good advantages of the battery ignition system, some limitations still occur. below are the disadvantages of the system in their various application:

  • It occupies more space.
  • Periodic maintenance will be required for the battery alone.
  • Efficiency decreased with a reduction in spark intensity.
  • The battery must be employed for the spark to be generated.
  • Faulty spark plug and battery won’t make the system work.
  • More maintenance might be required.

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In conclusion, the battery ignition system is also a great way of igniting the fuel-air mixture in spark-ignition engines. We have enlightened the definition, function, components, and also a diagram of the ignition system where we stated how important the battery was in it.  we also enlighten on its working as well as the advantages and disadvantages of the system.

I hope you enjoyed reading the article, if so, kindly comment on your fav section and please share with other technical students. You should check around for more interesting post. Thanks!

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