What Is an OPTO ESC? Let’s Find Out!

So, you often notice something called OPTO in ESC. But, in those cases, you can not figure out what it means. 

And you are now wondering what is an OPTO ESC?

OPTO ESC means an ESC without any BEC. It indicates a part of the ESC which is isolated from a higher voltage circuit. It’s the part that receives a signal from the RC receiver. It also prevents noise that arises from high-power ESCs. It helps with the electrical isolation requirements of ESCs too.

Not sure yet? Do not worry. Because in this article we provide you with the proper clarification of OPTO ESCs. Plus, including reasons why they can be so significant.

Keep scrolling to find out! 

What Is an OPTO ESC?

An OPTO ESC is an ESC that doesn’t contain any BEC. But how does ESC without any BEC work?

ESC without any BEC isolates the battery and motor from the controller’s receiver. Hence, the flight controller being isolated from a higher voltage circuit. As a result, the RC battery voltage difference is minimal. It has multiple advantages too.

OPTO ESC nowadays is very common on several multirotor setups. Because ESC does not always require a BEC to work. 

An OPTO ESC separates the high power side from the signal side. Here the high power side refers to the motor and battery. And the signal side refers to the connection to the receiver. 

The isolation takes place by internally sending the receiver throttle signal. That is, from the input side to the output side of your ESC via an OPTO-coupler. 

It is practically an LED transmitting a light signal. It sends the signal across a little gap to the photocell that receives it. Hence, no electrical connection exists between the two sides. 

So, OPTO is supposed to imply ‘OPTO-coupled’. Here the throttle signal would be coupled into ESC through a light beam. 

The notion is, that there’s no direct electrical connection existent between the receiver and the business end of ESC. Hence, halting electrical interference from moving down the wiring to the receiver.

Pretty simple, isn’t it? Well, at least we are not defining VCC on PDB here.
Nonetheless, there are some cheap ‘OPTO’ ESCs available that do not possess an OPTO coupler. And should simply be called ‘No-BEC’. In most applications, they would work just fine.

3 Reasons for Applying OPTO ESC

There are some obvious reasons why you need OPTO ESC. In certain circumstances, OPTO ESC enables a smoother workflow! Makes things way easier for you.

Below we have provided a few of them. Have a look at these and find out!

Reason 1: Prevents Noise

The high-power part of ESC tends to be noisy. It drives the motor. Then there is the signal wire which is associated with the receiver. 

The real OPTO ESCs have no electrical connection with either of them. 

And let’s not forget that it is called OPTO due to its OPTO-isolator. This utilizes light instead of the copper connection to deliver the signal.

Thus it prevents the noise from those high-power components. The noise that’s created while traveling down those wires and into the RX. Plus, every other thing it is connected to.

So, OPTO ESC is a good safeguard for extremely noisy and high-power setups.

Reason 2: The Voltage Difference in the ESCs

It is not pragmatic to have that high voltage BEC on ESC. For example, the ones which handle more than about 5 or 6 LiPo cells.

With a BEC the voltage difference will be too big. Plus, there will be too much heat produced.

For example, the nominal voltage of the 12S pack can be 44.4v. And maybe you expect any BEC to lower the voltage down to 9 volts. That means that it has to drop to 35.4volts. 

Understandably we are not calculating the battery size of the Traxxas E-Revo at least.

However, this is one daunting task to get done. Even if you are applying a switching regulator.

That is why OPTO is important. As it isolates the transmitter from the high voltage compartment. Thus, the voltage difference is lower than BEC.

For a 12S LiPo battery with OPTO ESC, the difference is below 3 volts. It is so little that it won’t have any significant negative impact.

Reason 3: You Can Turn Off OPTO ESC

Often there is an electrical isolation requirement on the logic or signal side of the ESC. And it can’t be powered off with an internal BEC. Rather it sucks power out of the motor battery. 

Also, it can potentially violate the electrical isolation between the power and signal or logic side.

So this type ESCs require power from the RX end to transmit power to their signal side. Or the logic side. 

The high-power side of your ESC usually is powered by the main motor battery. And part of the logic side tends to be powered from RX.

So, here comes the need for OPTO ESC!

But stay aware that some cheap ESCs can be labeled as “OPTO”. But they are not OPTO-isolated. They just do not have any internal BEC. Also, they require power for the logic circuits to be sustained from the receiver.

To avoid getting yourself a bad OPTO ESC, here are our recommendations.

So, there you go! Hope you do not have any further doubt about the usage of OPTO ESC. And why it is significant for a smoother run of remote control cars! 

Now the rest is your choice of how you want to use your ESC. Decide wisely. Here’s someone who carefully selected ESC for his first flight.

Frequently Asked Questions (FAQs)

How do I know if my ESC has BEC?

To tell whether your ESC has BEC, first look at all its components of it. You will find it on the back side of your speed controller. In maximum cases, the front label of the ESC would tell. You can also know whether it is a linear BEC or a switching BEC.

What is a UBEC used for?

A UBEC is an acronym for a universal battery eliminator circuit. It is simply a device that converts high voltage to lower voltages. For example, 25V from a 6S LiPo. Thus allowing the entire UAS to be powered from one main battery source.

What is the best type of ESC?

There is no good or bad type of ESC. As 2 types of Electric Motor are utilized to power RC Cars. They are Brushed and Brushless. Also, most ESCs are built to operate with only certain types of motor. For example, brushed ESC with a brushed motor. And brushless ones go with brushless motors.