Webinar

The basics of selecting e-powertrain components for small and medium off-highway applications

Every vehicle has its particularities and requires its own electric powertrain configuration. Whether it be the axle, the motor, the controller or the battery, each component of the e-powertrain must be selected according to the use of the vehicle. With this webinar, we will help you optimize the e-powertrain components of your off-highway equipment.

Electrifying a vehicle: Why it is not that simple?

When it comes to electrifying a small-size or midsize vehicle, it may look easy. The material handling industry has been doing it for many years for indoor applications like lift trucks. So why would vehicles be any different? Why not just use an existing vehicle as a template to build an electric one?

It’s not that simple…
You must consider many aspects of your application: not just the vehicle itself, but the conditions in which the vehicle will operate. There are many factors to consider that are sometimes neglected or outright ignored.

Common questions asked when electrifying a vehicle:

  • What kind of motor should I use?
    • DC – AC?
    • AC = Induction or PMAC?
    • PMAC = IPM or SPM?
  • What should the axle reduction ratio be to optimize the torque and speed?
  • What is the motor’s nominal RPM? Is this important?
  • How can I make sure the motor operates in its optimal efficiency zone?
  • What type of battery should I install?

All these questions are relevant, but they should not be your initial questions when starting an electrical project.

Instead, the question you should ask first is: “What will the vehicle’s purpose be?”

If you want to make the right choices to create an optimized electric system, you first must determine, before selecting any component, for which applications your vehicle will be used.

Depending on the answer, you can then start to define the specifications your vehicle will need.

Basic factors to take into consideration to define the performance you need from your vehicle:

  • Weight (empty and loaded)
  • Maximum slope
  • Desired maximum speed (at different conditions)
  • Acceleration speed
  • Surface (dirt/mud, asphalt, ice…)
  • Tires (surface + tires to determine the friction)
  • Weight distribution
  • Will the vehicle need to tow something?
  • Do I need extra motors (other than for the traction)?

Now that these elements have been taken into consideration, is it time to build the electric vehicle? Not quite. Let’s not forget the most important factor to evaluate: the duty cycle!

Often neglected, the duty cycle is one of the main factors to consider when electrifying a vehicle.

How much time, in percentage terms, will the vehicle spend at full speed?

How much time, in percentage terms, will it be fully loaded? On an uphill slope? On a downhill slope?

For example, I can design my vehicle to drive on a 25% slope while fully loaded, but I don’t expect it to be in this condition 100% of the time. Perhaps it will drive on a 10% slope more often, like 20% of the time. This is what we call the duty cycle.

It is not easy to figure out what the duty cycle of a vehicle will be when you are in the design phase, but you should at least start with an estimate.

The duty cycle is the key to optimizing the whole system (motor power, axle reduction ratio, operation point of the motor, type of motor, etc.) because it will help you figure out which components are right for your vehicle, not just in terms of torque and speed but also in terms of motor efficiency.

Duty cycle 20% uphill 5% uphill
Standard powertrain



Heavy duty powertrain		 Shortened lifespan Good choice
Good choice Oversized
Example of a Duty cycle

To illustrate the importance of the duty cycle, here is the torque/speed curve of a motor:

Video: Torque/speed curve of an electric motor

You must use a motor that has the right continuous power and can reach the required intermittent power. Beware of the kW (or horsepower) written on the nameplate, as it is not always clear what it means exactly (peak, 5 min, cont. 60 min? There is no standard). You must work with the motor curve.

This is where you begin to think about the type of motor. The peak vs continuous torque is different from one motor to the next.

You must also consider the desired efficiency.

Yes, PMAC motors are more efficient than DC motors and it is an important point to consider.

However, is efficiency the main requirement for the intended application? In a situation where you can plug your vehicle every 10 minutes, for example, it probably isn’t.

Conversely, for vehicles like UTVs, it is important not to run out of battery power in the middle of the forest. Therefore, having good efficiency (and battery autonomy) will certainly be an important factor to consider.

In the end, it is all about defining your needs and making good choices to satisfy them.

Here is a typical efficiency curve for a PMAC motor:

Video: Efficiency map of a PMAC motor

The main challenge here is to make the motor run within the optimal area (dark green area) as much as possible.

You can allow it to go further from that zone for intermittent use, but not too often, as it is going to affect the battery autonomy.

It’s a matter of compromise. In this context, the most important question to ask yourself is:

  • What are the appropriate motor power (cont. and peak), RPM, and axle gear ratio to meet all the operation points of the duty cycle while staying in the optimal efficiency zone AND without overheating the motor?

Figuring out the answer can be tricky, but it’s worth it to optimize your system, especially if you need high efficiency. If you choose to use a Li-Ion battery to extend the autonomy without optimizing the efficiency of the whole powertrain, it is not consistent.

Let’s wrap things up!

Before questioning yourself on what type of components you should use for your vehicle, you first must know what you intend to do with it and analyze the intended applications’ requirements. It is the key of a good design.

Finding the optimal solution requires complex calculations and engineering analysis. If you build a vehicle with a generic axle and motor, it may work. Chances are, however, that it will not run optimally, as it may encounter performance issues, its components may be oversized, and it may eventually suffer from poor battery autonomy.

If you are still confused and need expertise in the electrification process, look no further. Canimex is the partner you are looking for!

Start your project now

Who are we?

The Canimex Mechanical and Electrical Division is your preferred 360° electrification system integrator in North America. We specialize in integrating and optimizing power transmissions for off-highway applications.

We have experience in electrifying equipment in many markets, including e-mobility, municipalities, material handling, agricultural, construction, marine and many more.

Our solutions include e-axles, e-wheel drives, AC and DC motors, motor controllers, batteries, and many other mechanical & electrical accessories. We make the electrification process easy to help you bring all your projects to life!