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Aug 29, 2019, 08:33 AM
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How Rating of Electronic Speed Controllers for Drone is Determined

Electronic Speed Controllers, in short ESC, are indispensable parts of FPV drones as they function to connect the flight controller to the motor. This component takes the signal from the flight controller and gets power from the battery. The main function of ESC in a drone is to make the brushless motor spin. Brushless motors canít spin on their own because they are devoid of brushes i.e. commutators -which provide the physical contact of motor windings to spin the motor. Therefore, brushless motors require the help of ESC to spin.

To buy electronic speed controllers for drone, you should know about how ESCs are rated.

How are ESCs rated?

The ratings of ESCs depend upon how much current they can pass to the motors. What ESC has to do is to switch power on to the motor coils at extremely fast rates. This switching is controlled through the use of microprocessor and carried out by transistors called MOSFETs, which are commonly known as FETs.


How much current i.e. amperage can pass through the ESC is determined by the size and quality of these FETs. Most of the ESCs have ratings such as 30 amps or 25 amps. This magnitude generally represents the sustained current that an electronic speed controller can handle. For short durations, generally less than 10 seconds, ESCs are capable of handling more magnitude of current. For example, an ESC labeled as 30 ampere is capable of a 40 amp burst.

The amp rating is an important factor to consider when you buy electronic speed controllers for drone. It is often better to buy an ESC capable of handling more current at the cost of size or expense rather than buying an ESC with small current rating that might be damaged by too large current.


Most of the drone operators generally use 4S batteries that operate at 16.8 volts. However, recently, the trend has changed. Nowadays, various race organizers are encouraging pilots to use 5S and 6S batteries of higher voltage. Some ESCs are rated for 3S-4S. The power of motors can be measured in watts, which is the quantity obtained by multiplying voltage by amperes.

Therefore, as the voltage increases, amperage may decrease to keep the total power output of the motor the same. This eventually means that the higher voltage batteries can offer the same motor output power at a lower current draw. Alternatively, if the voltage is increased and pilot chooses to give a lot more throttle, the current draw will also increase. This will result in increased total power of the motor and therefore, a higher voltage drone will flyer faster than a lower voltage drone.

Once you figure out what voltage and amperage are ideal for your drone application, it would be easy to buy electronic speed controllers for drone online.
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