How to Convert Your Petrol Car to an Electric Vehicle

If you are attached to your petrol car or own a classic and want to make the switch to an EV, one option is to convert your existing petrol car to electric. This may seem like a daunting task, but with the right guidance and information, it is possible to convert your petrol car to an electric vehicle.

In this article, we will explore how to convert a petrol car to an electric car, how much it costs and what are the challenges of a conversion.

pertrol BMW parked with the bonnet up ready to work on

Can I convert my petrol car to electric?

Converting a petrol car to an electric car is a fascinating project that is gaining popularity among car enthusiasts. This process involves replacing the car’s internal combustion engine with an electric motor and equipping the vehicle with a battery pack to store electricity. While the idea might seem straightforward, the conversion is very complex and needs thorough planning and consideration of several important factors to make it work.

The suitability of the vehicle for conversion is one of the first considerations. Not every petrol car is a good candidate for electrification. Factors such as the vehicle’s weight, size, and original design play crucial roles in determining whether a conversion is practical. Lighter vehicles, for instance, are often preferred because they require less energy to move, which can lead to better efficiency and a longer range on a single battery charge. the cars also need sufficient space to house the electric motor and the battery pack without compromising its structural integrity or safety.

To make it you need to convert several key components. The electric motor, which replaces the petrol engine, is vital for the vehicle’s propulsion. The choice of motor significantly influences the converted EV’s performance, including its speed and acceleration.

Equally important is the battery pack, which determines the vehicle’s range. Finding a balance between battery capacity, weight, and the available space within the vehicle is a complex challenge. Additionally, a controller is needed to regulate the power flow from the battery to the motor, and a charging system must be installed to enable the battery’s recharging from the grid. Some conversions might also require updates to the vehicle’s cooling system to manage the heat generated by the electric components, and decisions about the transmission system can affect both the complexity of the conversion and the driving experience.

However, undertaking an EV conversion requires not only a significant financial investment but also a high level of technical expertise in both automotive engineering and electrical systems. Regulatory compliance is another critical aspect, as the converted vehicle must meet all safety standards and emissions regulations to be legally driven on public roads.

Is it legal to convert a petrol car to electric?

It is legal to convert a petrol car to electric, but there are specific requirements that must be met. Any converted vehicle must take an Individual Vehicle Approval (IVA) test to make sure that it meets the necessary safety standards.

The IVA test includes inspections of the converted vehicle’s braking system, suspension, steering, and electrical components, among other aspects. The most important part of the test is to make sure that the converted vehicle meets the zero emissions standards set by the government.

How do you convert a petrol car to electric?

Converting a petrol car to an electric car involves a huge amount of work and expertise in both mechanics and electrical engineering. Here are the general steps involved in converting a petrol car to electric:

  1. Remove the engine
    The first step is to remove the old engine, fuel system, and exhaust system.

  2. Install electric motor and batteries
    A suitable electric motor needs to be chosen and installed in the car. The batteries should also be chosen and installed in a manner that balances the car’s weight distribution. The electric motor should be connected to the car’s transmission or drive shaft, remember, EVs do not have gears like traditional ICE cars.

  3. Wiring the new system in
    The electrical system needs to be rewired to accommodate the new electric motor and batteries. This requires expertise in electrical engineering and programming to ensure that the car operates correctly and safely.

  4. Cooling and heating systems will be needed
    The electric motor and batteries generate heat and require a cooling system to prevent overheating. The car’s heating system may also need to be modified to run off the electric power.

  5. Testing and fine-tuning
    Once the conversion is complete, the car needs to be tested to ensure that it operates safely and efficiently. The car’s performance may need to be fine-tuned to optimize its range and power output.

  6. Apply for an Individual Vehicle Approval test
    You need to fill in this IVA 1C application form for passenger cars with less than 8 seats.

Companies that convert petrol cars to electric

Converting a petrol car to an electric car is a really complex process and there are plenty of companies around who will complete that conversion for you. Let’s look at some of the options:

London Electric Cars
London Electric Cars are based in London and specialise in converting petrol cars to electric. They offer a range of conversion options, from basic conversions to complete restorations.

Electrogenic are from Oxfordshire, Electrogenic specialises in converting classic and vintage cars to electric. They also sell ready-to-drive electric classic cars. 

Electric Classic Cars
Electric Classic Cars, based in Wales, convert your classic to electric, building your electric classic to your specifications.

How much does it cost to convert a car to electric?

The cost of converting a car to electric can vary widely depending on various factors such as the size of the car, the type of electric motor and batteries used, the range and performance desired, and the complexity of the conversion. However, a general estimate for converting a petrol car to electric in the UK is between £20,000 to £30,000.

This cost includes the electric motor, batteries, controller, charging system, and other necessary components, as well as the cost of labour for the conversion. The cost can be higher for larger or more complex cars or for those that have had a lot of customisation.

It is probably a lot more cost-effective to buy an electric car from a manufacturer instead of attempting a conversion. Additionally, government grants and incentives are available to new EVs that are not applicable to conversions, which further adds to the appeal of a new EV over a conversion.

Can you convert a petrol car to an electric hybrid?

It is possible to convert a petrol car into a hybrid, but it has a unique set of challenges and complexities compared to a full electric conversion. This process, known as a hybrid retrofit, involves integrating an electric propulsion system alongside the existing internal combustion engine.

Key components of a petrol:hybrid conversion

  1. Electric Motor: Adding an electric motor to a petrol car is central to a hybrid conversion. This motor works in tandem with the car’s original engine, providing additional power that can be used for acceleration, improving efficiency, and reducing reliance on petrol.
  2. Battery Pack: A significant battery pack is required to store the electrical energy needed to power the electric motor. The size and capacity of the battery will directly influence the electric-only driving range of the hybrid vehicle. Integrating a sufficiently large battery into the existing vehicle structure without compromising safety or passenger space can be a complex engineering challenge.
  3. Hybrid Control System: Another important component of the conversion is the hybrid control system. This advanced electronic system manages the interaction between the petrol engine, the electric motor, and the battery pack. It determines when to use electric power, when to use petrol power, and when to recharge the battery (typically during braking or while running on petrol power). Developing or adapting a hybrid control system that can efficiently manage these tasks is essential for a successful conversion.
  4. Charging System: For plug-in hybrid conversions, an external charging system is necessary to allow the battery pack to be recharged from the electrical grid. This involves installing a charging port and onboard charger capable of converting AC electricity from a standard outlet to DC power for charging the battery.
Landrover sport hybrid charging on a driveway
Hybrids are more complex conversion projects as they use both electric & petrol motors

Integrating these components into a vehicle not originally designed to accommodate them requires significant engineering expertise. The placement of the electric motor and battery pack must be carefully considered to maintain the vehicle’s balance, safety, and structural integrity.

The cost of a hybrid conversion can be substantial, not only due to the price of the components but also because of the labour involved in customising and integrating these systems into an existing vehicle.

Can I convert a classic car to electric?

It’s fine to convert a classic car to electric, lots of classic cars have been converted over the years. There are several advantages to converting a classic car to electric, including improved performance, reduced maintenance, and the environmental benefits of using an electric powertrain!

Converting a classic car to electric presents a unique set of challenges, some of which include:

  • Space constraints
    Classic cars often have limited space for accommodating modern EV components, such as the battery pack, electric motor, and charging system. Custom solutions may be needed if you are going to fit everything in.

  • Weight distribution
    Adding a battery pack and electric motor may change the weight distribution of the vehicle, which can impact its handling and performance. Careful planning and placement of components are needed to help maintain the vehicle’s balance.

  • Preservation of original appearance
    Maintaining the classic car’s original look is important. This might involve finding creative solutions to integrate the EV components without altering the car’s exterior or interior too much.

  • Integration of new and old systems
    Classic cars often have older, less sophisticated electrical and mechanical systems that may not be directly compatible with modern EV components. Integrating the new components with the existing systems can require a good understanding of both the old and new technologies.

  • Availability of parts
    Some classic car parts might be rare or difficult to find, which can make it challenging to adapt the vehicle for an electric conversion. Custom fabrication or modification of parts may be necessary in some cases.

Can I convert a diesel car to electric?

It is possible to convert a diesel car to electric in the same way that you would a petrol car. The process is the same, but there are a few additional considerations for owners of diesel cars:

Diesel engines are generally heavier and larger than petrol engines, which may affect the weight distribution and available space for the electric components.

Diesel vehicles typically have higher torque and lower RPM ranges than petrol vehicles. This may mean that you have to select an electric motor that can provide a similar driving experience.

What’s the easiest car to convert to electric?

The easiest car to convert to electric is typically a small, lightweight vehicle with a simple mechanical layout and loads of space for the parts needed, such as the battery pack, electric motor, and charging system. Some popular models for electric conversions in the UK include the Volkswagen Beetle, Porsche 911, Mazda MX-5 Miata, and various classic British roadsters like the MG Midget or Triumph Spitfire.

Is there a kit to convert a car to electric?

There are plenty of electric vehicle conversion kits on the market that can help you convert a car to electric. All of the conversion companies listed in this article sell conversion kits.

The kits usually contain an electric motor, motor controller, charger, batteries, and all the other parts you need like wiring harnesses, contactors, and fuses.

Double (and triple) check that the kit is compatible with your specific car, some kits are designed for particular cars, while others may be more generic. Also, check that the kit includes a charging system compatible with your home charger, the best EV charger installers will be able to advise on the compatibility. Also, check the charging infrastructure in your area and that the company selling the kit provides customer support and aftercare if needed.

Can I still use public chargers with a converted car?

Yes, you should still be able to use public chargers with a converted car, as long as your car’s charging system is compatible with the charging stations available. You might find that you are unable to use fast or rapid chargers. Do some research on charging connectors available at the charging stations in your area and make sure the system you are using for the conversion is compatible.

Evolt ev public charger
Double-check that your conversion kit can use public chargers in your area

Are there any downsides to converting a petrol car to an electric car?

So far in this article, we have looked at how to convert a petrol car to an EV, we should run through the potential downsides for you to consider before taking the plunge!

  • The cost is high!
    EV conversions can be expensive, depending on the components and labour required.

  • Missing out on EV safety features
    Morden EVs have a range of safety features that converted cars will not benefit from. Such as automatic emergency braking, regenerative braking and blind-spot monitoring systems.

  • Range limitations
    Depending on the battery capacity installed during the conversion, the range of the converted vehicle will generally be less than that of an electric vehicle you can buy new. 

  • Resale value
    A converted electric vehicle may have a lower resale value compared to an original electric vehicle or an unmodified petrol car. Potential buyers might be concerned about the quality of the conversion and the availability of replacement parts and support.

  • Technical expertise
    Converting a car to electric requires a certain level of technical expertise and mechanical skill. If you’re not experienced in this area, you may need to rely on a professional, which can add to the cost.

  • Warranty
    Converted vehicles usually do not come with the same level of battery warranty and support as electric vehicles that you buy new, which can be a concern if you encounter issues with the conversion.

MORE> The Disadvantages of Electric Cars

The final word on converting your petrol car to electric

Converting your petrol car to an electric vehicle could be a great project for someone with mechanical and electrical know-how. If you get it right, you will enjoy the benefits of lower operating costs, reduced emissions, a quieter mode of transport and improved performance.

You really need to carefully plan and research the process, taking into account factors such as the choice of components, space constraints, weight distribution, and legal and regulatory compliance.

It’s a complex job and luckily there are plenty of expert companies out there for you to speak to and take advice from.

Electric Car Guide logo

Supercharge Your EV Knowledge

Editorial Independence

icon of a rosette with a tick in the middle, symbolising trust

Our articles are written independently.
Products are reviewed objectively and rated
without influence from advertisers.

Expert Opinions

icon of a team of people with a light bulb above their heads, indicating they are thinking as a team

We keep up to date with the world of EVs.
We continually revise our articles as technology changes.

Accurate Information

Icon of a head with an arrow pointing up

Electric Car Guide is committed to a
thorough fact-checking process.
Our Editorial Guidelines explain how we achieve this.