What Is an ESC For RC Cars?

Most RC cars have similar components to real cars, with one major exception: the ESC. Newcomers to the hobby commonly ask what is ESC and whether they need it for their RC car?

ESC, or Electronic Speed Control, is a circuit board that you can add to your RC car that automatically controls some aspects of speed, reversing, and braking. It is helpful for racing RC cars since its most popular use is automatically applying the brakes when turning corners to avoid skidding.

ESCs have gotten better over the last few years, and developers keep adding more features. Because of this, they can become quite confusing, and it could be challenging to determine which one you need or if you even really need one.

Let’s look at some of the details on how ESCs work and what you can do with them, then you can make an informed decision.


How Does An ESC Work?

An ESC, in basic terms, is a small circuit board or tiny computer that dynamically determines how much power it should provide to the motor. It also provides baseline power to the servos, transmitters, and other basic components. 

Electric motors are inherently simple devices: the more power they’re given, the faster they spin. However, the motors don’t have any way to regulate themselves. 

That’s where the ESC comes in. 

The ESC controls how much power flows from the battery to the motor, thus controlling how fast the motor spins. It also controls the direction the motor spins, but we’ll get into that in more detail next. 

Traxxas VXL-3S ESC

What Else Does an ESC do in an RC Car?

Controlling the amount of power to the motor is the basic function of all electronic speed controllers. But that led to people coming up with new ways to implement the technology.

Hence we have a range of new ESC functions available today that some RC car enthusiasts may enjoy.

Now let’s look at some of the ESC’s other uses:

Reversing

Your RC car’s motor will have two or three wires, depending on whether you have a brushed or brushless motor. How these wires are connected to the battery matters because one way will start the forward movement while flipping them around will reverse the car.

The ESC takes over this reverse capability, crossing the paths of the wires when you reverse so that you don’t have to cross them manually. So when you tell the RC car to reverse, the ESC takes over, reroutes the flow of electricity to the motor, and starts to run in reverse.

In modern RC racing cars, the reversing ability of the ESC is often removed since the idea of a race is only to move forward. This way, you avoid any accidental reversing or confusion during the race.

Braking

Modern ESCs can help your car brake faster by adding a dynamic braking capability. They flood the motor’s armature with electricity, effectively turning the motor into a generator.

This makes it harder to turn the armature, forcing it to an almost immediate stop. 

This is a form of braking known as “regenerative braking,” which turns one type of energy into another. This method converts the kinetic energy from the motor’s movement into electric energy, which some models can even store to supplement the battery.

Dynamic braking must be supported by your ESC, the motor, and the controller.

Boost And Turbo Through The ESC

If your ESC supports it, you can use it to enable either Boost, Turbo, or both.

Before we explain this process, keep in mind that both Boost and Turbo increase the motor’s timing which causes it to run hotter.

This could reduce the motor’s life or even burn it up instantly if you’re not careful. Make sure that you understand the limitations and capabilities of your motor before attempting this.

First, we need to understand the difference between Boost and Turbo. Boost is applied across a set range of RPMs.

For example, your Boost can be configured to run from 5,000 to 20,000 RPM. That means that, between these ranges, your motor’s timing will be increased by a certain amount.

Turbo kicks in once you’ve reached full throttle, where it adds some additional degrees to your timing.

Some drivers prefer either Boost or Turbo over the other, and that’s fine. But if your hardware supports it, there’s no reason not to use both.

Using the ESC for this is much better than manually adjusting the timing on your motor since it gives you more control, and you can make finer adjustments.

Using Turbo and Boost through the ESC lets you get a lot more speed from your RC car on straightaways or easy corners. However, you’ll lose some torque and stability simultaneously.

Be extra careful not to use either one around corners or where you need the added traction.

Increasing Torque

Like how you can use an ESC to change the timing on your motor to add speed, you can do the opposite and let your ESC add torque.

Increasing the timing on your motor will increase speed, while decreasing it will add torque. If your race has a difficult uphill part, temporarily letting your ESC reduce your timing will help you cross that.

Low Voltage Protection

Over-discharging a LiPo (Lithium Polymer) battery can lead to permanent damage. 

Many ESCs are designed to detect whether you’re using a LiPo battery so they can automatically cut power to the motor before the voltage gets too low. 


Do I Need An ESC For My RC Car?

Whether you know it or not, you probably have an ESC because almost all RC vehicles (not just cars) have them. 

If you are still building your RC car, you have the freedom to choose the type of ESC you need. 

For example, suppose you will be participating in hardcore speed races. In that case, it’s good to get one with Boost and Turbo, along with dynamic braking. Reversing is not so important, though.

Or, if you prefer the “off-road” style, you don’t really need so much speed. It might be good to opt for an ESC with adjustable torque, dynamic braking, and reverse.

Anyone who’s even a little bit serious about their RC cars will need an ESC, but which one you choose is up to you.

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