Electric Car Components and Functions

Advances in fuel efficiency, adherence to environmental standards, and global ecological sustainability measures are all becoming increasingly important in today’s society.

Electric vehicles are becoming a part of modernity; their efficiency and non-reliance on fossil fuels have piqued the interest of environmentally conscious drivers across the world.

Beyond the environmental standpoint, drivers are also drawn to electric vehicles (EVs) due to their low running costs, notably electricity being much cheaper than petrol and diesel. The two aforementioned are pushing both the new EV market and the electric car conversion market sky high.

Classic car upcycling and electrification is now economical and much more achievable than it was even 2-3 years ago.

Did you know that you can upcycle and change your vehicle from petrol/diesel power to electric power?

Within the current innovative era of vehicle manufacture, modern electric cars are still too pricey for most people, and there is a scarcity of secondhand electric cars for sale. Rather than choosing a dazzling new model, drivers are deciding to convert older cars by replacing the engines and transmissions from existing diesel and petrol vehicles and substituting them with batteries and electric motors.

If you’re considering converting your car to electric, there are a few things you should know. As the fundamental mechanisms of electric vehicles differ greatly to those of petrol/diesel engines, today we explore the primary components and functions of an electric car conversion in order to show how it all works.

How does an Electric Car work?

Instead of an internal combustion engine, electric cars are propelled by an electric motor. The motor is powered by a high-voltage battery pack which feeds electricity to the motor based on how far you push the accelerator pedal.

When the vehicle’s accelerator pedal is pressed, the following happens:

  • The motor controller (inverter), as the brain of the operation, receives the input and calculates how much power is needed from the battery pack.
  • The inverter then sends an amount of electrical energy to the motor based on how hard the pedal is pushed.
  • Electrical energy is converted into mechanical (rotational) energy by the motor using electromagnets and wire coils.
  • The output shaft on the motor rotates inside the transmission.
  • The transmission adjusts this rotation into a speed that can be used by the rest of the drivetrain (axles, differentials, driveshafts etc) causing the wheels to turn and the car to move.

Main Components of an Electric Vehicle

Battery Pack

The most significant component of an EV is the battery pack. It’s the biggest and most expensive component and ultimately determines how much power and range the vehicle will have. The battery pack is made up of a number of separate batteries that are linked together, this can be anything from 5 to 25 batteries, which each consists of hundreds of individual cells and usually come out of production electric vehicles.

The battery pack will be housed in a custom-built metal battery box which is designed to fit into the original engine bay of the classic vehicle. If more batteries are required for additional range, a second battery box can be installed somewhere else (in the boot or under the back seats for example).

In this battery box are all of the electronic components which control and monitor the pack. For example, an ignition system will open and close switches to turn the car off and on.

Also within the battery box is the battery management system (BMS) which monitors voltages, temperatures, and the current running through the pack whilst charging and discharging, ensuring that the battery is not damaged by excessive temperatures or voltages.

This BMS links to the charging system and motor controller, constantly sending and receiving signals to ensure that the battery pack is operating optimally.

Finally, the battery box has a cooling system running through it connected to an external radiator and water pump. This cooling system runs coolant inside each battery within the pack to ensure that all batteries are running at the same temperature and that this doesn’t get too high, which would in turn limit the motor output.

Image: EV battery pack (Electric Car Converts)

Power Inverter/ Controller

The inverter (which is also called a motor controller) converts direct current from the batteries to alternating current, which is subsequently delivered to the motor. Think of it as the link between the battery and the motor, without it, the motor would spin at full speed the whole time.

This motor controller will be connected to the throttle of the vehicle as well as the battery management system.

Inverters have a lot of current running through them, particularly if you’re driving quickly, so they’re also linked to the battery cooling system, allowing coolant to keep the temperature manageable.

Finally, the electrical vehicle inverter can convert alternating current to direct current during braking, which can subsequently be utilized to recharge the battery, this is called regenerative braking.

Image: Power Inverter/Controller (Electric Car Converts)

Electric Motor

The motor converts electrical energy into mechanical energy to drive the wheels and propel the car. Motors vary hugely, some runoff direct current (DC), some off alternating current (AC). The most common motors for electric vehicle conversions are AC due to them being more efficient. A motor is effectively a large electromagnet that turns due to the attraction and repulsion of the magnets within.

Electric motors convert over 85% of electrical energy to mechanical energy as compared to less than 40% for a gas combustion engine. (Source: NRDC.org)

Electric motors vary in size and power. For example, a motor that could be mounted in an average classic car would be around 120 horsepower, whereas a Tesla large drive unit can generate upwards of 500 horsepower if required.

The motor turns the transmission (gearbox), which can be either the original one or a single speed unit specifically designed for electric power. Using the original gearbox lowers the cost of converting a classic car to electric power as there is little fabrication of new drivetrain components and only adapter plates are required.

However, if using a Tesla drive unit, for example, this has to be mounted across an axle and therefore needs custom half-shafts, differentials, and drivetrains – significantly increasing cost.

Other Components in an Electric Vehicle


A charger is a device that converts AC which comes out of the grid, into DC which in turn charges the electric vehicle batteries where that energy is stored.

Chargers in electric vehicles have to be smart to ensure that they charge the battery pack at a suitable speed. A charger is mounted within the car so that the batteries can be charged wherever the car is, whether this be at home, at a carpark or at a motorway service station.

Image: Electric car charger (Electric Car Converts)

Chargers come in various powers, which can greatly affect how fast a car will charge up. However, even the fastest charger available will not be able to charge quickly if the power source is not large enough.

For example, the power that comes out of a standard UK plug can only charge a car at a maximum of 2-3kWh, whereas a wall-mounted charge system, such as one that you can get installed in your home or you’d find at service stations can charge at 10kWh or more!

Our team at Electric Car Converts highly recommends getting an electric car charger installed in your home, and our partners Go Electrik will be happy to help with this!

DC/DC Converter

The DC/DC (direct current) converter is a device that transforms and changes higher-voltage DC power from the high-voltage battery system to the standard 12V battery required to operate the original 12V system.

This system comprises the lights, wipers, and central locking system for example. It means that upon conversion the car doesn’t have to have its 12V system rewired, which would account for a significant cost.

Thermal System (Cooling)

Although electric vehicles are 85% efficient, there is still some heat generation, which although is usually not extreme, to protect the components and keep them operating optimally it is best to keep them cool.

Many parts are aircooled, however the batteries and motor controller (inverter) must be kept cool. This thermal system comprises a very small radiator, a fan, a coolant pump and pipes to keep the coolant circulating. It is a closed-loop system that uses fluid to transfer heat away from the heat sensitive components.

The electric car cooling system has three main parts:

1. Radiator: this component cools the coolant fluid within the system.

2. Coolant: this fluid helps to transfer heat away from the electric car components.

3. Fan: this component helps to circulate cool air into the coolant, particularly in slow traffic when air movement is minimal.

Charging Port

The charging port will usually be mounted where the original fuel filler is. It connects directly to the charging system within the car which in turn charges the high-voltage battery pack.

Electric conversions in the UK and Europe usually use Type 2 plugs, which are standardized to ensure the car can be charged up at different places without having to carry around adapters or expensive cables.

Most people don’t realize that you can charge up an electric car conversion using a normal 3-pin socket in the UK. Although slow, this allows you to not worry about finding a charging station. At electric car converts our battery packs can charge from 0-100% in around 8 hours out of a normal plug, although this is just 4 hours if using a purpose-built wall-mounted charging station.

Image: Converted Electric Land Rover – NEW charging port (Electric Car Converts)

Electric Car Converts Concludes

Electric vehicles are the future of automotive transportation. In order for electric vehicles to replace gas cars, a shift in thinking and technology needs to happen.

With the continuous development of technology, electric cars will become more and more affordable and popular. There are many different parts that work together to make electric cars work and most of these components are new to general drivers – so we hope that this guide helped!

Electric Car Converts are experts in all things EV conversions and will be pleased to answer any questions you may have about electric car conversions!

Reviewed by Barnaby Birkbeck (Founder) & Toby Wilson (Head Electrical Engineer), in 2024.

This article has been reviewed by our team of professional experts for accuracy and relevance. However, the information provided is for general informational purposes only. We recommend consulting with us for personalised guidance.