Converting a combustion engine to an electric motor is quite the project, especially if you plan on doing the work yourself. But if you’ve already got the frame and body of the vehicle, all you need to do is swap out the components. Still, you’ll want to make sure you’re choosing the right motor for your conversion because electric motors are not a one-size-fits-all kind of deal.
You typically need to consider the weight and size of the platform. Some motors also require extra parts, and certain car bodies may not have enough space.
To help you choose right, let’s review some of the best electric motors for car conversions, their specifications, disadvantages and advantages, FAQs, and more.
- DC Brushed Electric Motors
- Brushless DC Electric Motor (BDCM)
- Three-Phase Alternating Current (AC) Induction Motors
- Permanent Magnet Synchronous Motor (PMSM)
- Different Cars and Their Motor Types
- How Much do Electric Car Motors Cost?
- Car Conversion FAQs
- EV Speedy’s Take
DC Brushed Electric Motors
The brushed DC motor has been around for a long time, and it was the go-to motor for a lot of applications. This was primarily due to its low construction costs and simple operation.
While these types of motors are widely used today, you won’t see them as often in high-performance, fully-electric vehicles. However, that doesn’t mean they wouldn’t work for your car conversion.
These motors consist of two magnets that encase an electromagnet-containing rotor. This rotor spins when an electric current is introduced, but it only goes 180 degrees. It’s the contact with the carbon brushes that allow the poles to shift and the motor to spin the full 360.
Advantages of Brushed DC Motors for Car Conversions
The biggest advantages of this type of motor include:
- They have a high initial torque, which means they work well for those that need to achieve high speeds quickly.
- They’re generally the more affordable option.
- They have a simple operation and lack some electronic parts that other motors will require.
Do you want to nerd out further and find the exact differences between Direct Drive and Transmissions? Then check out this related and helpful article that I wrote called:”EV Direct Drive vs. Transmission Compared“. I discuss the Pros and Cons of both.
Disadvantages of DC Brushed Electric Motors
The brushes contained within these motors are one of the biggest disadvantages. They require a lot of maintenance and create a lot of friction. The friction may not only produce sparks, but it also generates heat, making these motors harder to keep cool.
Other disadvantages of these motors include:
- These motors often struggle at maintaining high speeds and often have a lower speed range.
- They might be noisier than other types of motors.
- Less efficient than many other motor types.
Brushless DC Electric Motor (BDCM)
The brushless DC motor was created to solve the problems created by the brushes in the DC motors.
The operation of the BDCM is essentially backward, where the magnets are on the rotor, and the surrounding electromagnetic field makes the rotor spin. Computers control the electric current, which means the BDCM requires additional devices that the brushed motor does not.
These motors are commonly used in smaller vehicles and hybrid cars, but you might also find them integrated into fully-electric machines.
Advantages of the BDCM for Car Conversions
The primary advantages of the BDCM include:
- Without brushes, they require less maintenance.
- Since there are no brushes that can potentially spark, a BDCM can operate at higher speeds for longer.
- They operate at a higher efficiency than the brushed motors.
- They are quieter than brushed motors.
- Less heat is generated, meaning the motor is easier to keep cool.
Disadvantages of the BDCM for Car Conversions
The main disadvantages include:
- You need a controller to keep the motor powered, which adds to the operational cost.
- They might experience periodic changes in torque, also known as a ripple.
Three-Phase Alternating Current (AC) Induction Motors
The AC induction motor has been around since the late 1800s, but it has seen many design improvements throughout the twenty-first century. Now, it’s commonly found in the Tesla Model S and some vehicles from other popular EV makers.
The induction motor doesn’t contain any magnets in the rotor. The magnetic field surrounding the rotor forces it into a spin. As a result, the rotor always rotates slightly slower than the rotation of the magnetic field, making induction motors asynchronistic.
On that note, I wrote a related article about Permanent Magnet Motor vs. Induction Motor Compared. I also provide pros and cons with detailed analysis. Check it out!
Traditionally, AC induction motors were more expensive than DC motors, but they’ve caught up in recent years and might even be more affordable in some cases.
This YouTube video gives a more in-depth breakdown of how induction motors work.
Advantages of AC Induction Motors for Car Conversions
Advantages for the AC induction motor include:
- Like the brushless DC motors, AC motors don’t require brushes, making them quieter, safer, and lower maintenance.
- A simple, robust design makes AC motors maintain performance in rough terrains and environmental conditions.
- A power converter can reduce voltage when necessary, which maximizes efficiency while reducing magnetic losses.
- When braking with an AC induction motor, the rotor begins to spin faster than the magnetic field. As a result, these motors have regenerative properties that send power back to the vehicle’s battery.
- They are often better for longer, rougher trips.
Disadvantages of AC Induction Motors for Car Conversions
On the flip side, AC induction motors have some disadvantages, including:
- They require a power inverter, which means more parts and a higher starting cost.
- Torque performance might be lower compared to some DC motors.
- Induction motors can be harder to control and stabilize, which might also increase costs.
Permanent Magnet Synchronous Motor (PMSM)
As the name suggests, a PMSM uses permanent magnets inside the rotor, so instead of being pulled by an electromagnet, the rotor itself acts as the electromagnet.
Similar to the induction motor, the PMSM must be connected to an AC supply. However, unlike an induction motor, the PMSM is synchronous as opposed to asynchronous, meaning the rotation of the motor is in sync with the frequency of the AC supply. This keeps the speed of the rotor constant.
There are plenty of high-performance electric vehicles that utilize the PMSM. You can find them in the Tesla Model 3 and certain versions of the Model S, for example.
Advantages of a PMSM for Car Conversions
Due to the permanent magnet setup and the AC power supply, the permanent magnet synchronous motor is advantageous for several reasons, including:
- Torque is constant regardless of speed. This means they can maintain high torque at lower speeds and won’t experience slippage or torque ripple.
- Power density is high, meaning they have high power output compared to the size of the motor (which is small).
- They’re small in size and simple in design.
- The full-load capacity is higher than that of an induction motor.
- The lack of brushes and internal friction make them low maintenance and easy to cool.
Disadvantages of a PMSM for Car Conversions
The disadvantages of these types of motors include:
- They require the use of “rare earth metals” and sometimes have a high initial cost, which may not be ideal for a conversion on a budget.
- A PMSM will require some additional parts like a controller or inverter.
- They are sometimes more difficult to start than other types of motors.
Different Cars and Their Motor Types
Different brands use different motors, and some car models use multiple motors to combine features of more than one type of motor. The Tesla Model 3, for example, uses an internal permanent magnet synchronous reluctance motor (IPM-SynRM), which combines features from the PMSM and the synchronous reluctance type motor.
While reluctance-style motors are gaining some traction, most EV manufacturers are using versions of the motors mentioned above.
|Model||Motor Type||Horsepower||Max Speed||Hybrid|
|Chevy Volt||PMSM||149 hp||98 mph (160 kph)||Yes|
|Tesla Model S||AC Induction||670 – 1,020 hp||171 mph (275 kph)||No|
|Nissan Leaf||DC Brushless||147 – 214 hp||90 mph (145 kph)||No|
|BMW i3||PMSM||170 – 181 hp||93 mph (150 kph)||No|
|Mercedes EQC||AC Induction||402 hp||112 mph (180 kph)||No|
|Ford Mach-E||PMSM||266 – 488 hp||130 mph (209 kph)||No|
How Much do Electric Car Motors Cost?
Before you begin converting a car to electric, you will have to set a budget and determine the cost of each of the components.
Electric car motors range from $1,000 to $15,000 or more. The cost varies dramatically depending on your requirements for power, torque, and efficiency, among other things.
Some electric vehicles are also equipped with more than one motor, with many high-performance EVs using one motor to power each wheel. With that in mind, you’ll have to decide how much motor power you’ll be needing.
All motors are going to come at a different price, but it might also depend on where you purchase the motor from.
The Different Options for Purchasing an Electric Motor
Sellers of EV motors and parts are growing in number. And with the increasing demand for electric vehicles, they will continue to do so. This also means that the used market for electric car parts will continue to grow as well, which is potentially good news for those interested in car conversions.
There are also plenty of companies that specialize in the sale and production of EV motors. As always, these places tend to be more predictable than a random seller on a marketplace.
Some of the big car manufacturers also sell motors specifically for custom conversions. For example, you can buy Ford’s 281-HP Eluminator electric motor for just under $4,000.
In some cases, you might be able to find a wrecked electric vehicle that has most, if not all, of the parts you’d need for conversion, including the motor. If you’re lucky enough to get your hands on something like this, it could be the most cost-effective option.
Car Conversion FAQs
Here are some of the most critical car conversion FAQs:
What Is the Best Kind of Motor for an Electric Car?
The AC induction motor is the best motor for an electric car. It’s cheaper to buy and low maintenance due to the lack of commutators, slip rings, and brushes.
What Are the Best Cars To Convert to Electric?
The best cars to convert to electric are classic models of Volkswagen and Porsche with air-cooled engines. That’s because their size, design, and weight make conversions easy.
They’re also relatively cheap to buy, helping keep the conversion costs low.
With that said, most of the companies that specialize in the retro-fitting of electric motors on classic body styles can also build electric vehicles out of virtually any car model.
The absence of brushes also makes these motors suitable for rugged conditions, as it eliminates the main cause of sparks in motors.
EV Speedy’s Take
Some of the most popular EV manufacturers, like Tesla, are using AC induction motors and PMSMs in a lot of their models, so you can have some confidence that these motors would provide the performance and reliability that you need in a vehicle.
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