Part of owning an RC car is accepting that the parts inside of it cannot last a lifetime, with many motors, gears, wheels, and bearings dying after some time. However, that does not mean that you need to accept that your motor or ESC has burned up.
Your motor may burn out when the amperage on it has been overloaded, or someone has held the RC car down while pressing on the throttle. An ESC will usually burn up when the current is too high, not enough cooling has been provided, or simply getting too dirty and shorted.
The reasons behind your motor and ESC burning out can be extremely varied, with many people not fully understanding the impact of their actions on the circuits inside their cars. We always recommend that you become completely familiar with the reasons an ESC and motor burnout to prevent the worst.
What Are the Reasons That an ESC Can Burn Up?
Motor burnout is much more likely to happen than ESC burnout, as the wear and tear on the motor are much more than on the ESC. However, when the ESC does burn out, it can be for many reasons, each one easily burning out the next ESC that you install in your RC car.
We recommend becoming familiar with the seven most common reasons that your ESC has burnt out and why you should check these things before replacing the ESC. We have seen several people that have been severely burned as they always replace the ESC without ever actually fixing the cause of burnout.
Current Too High
Current is the total amperage of the power entering the ESC or any other electric system of the RC car. Every component is rated up to a certain level of amperage, above which the circuits on the part begin to break and will no longer work properly.
A high current can be caused by the battery being shorted during operation, the motor overheating, or even feedback from the motor not being properly absorbed. The ESC has some safety systems for these issues, but if the amperage becomes too much for a split second, the ESC will completely fail.
Battery Voltage Too High
The voltage is what accompanies the amperage of the power system, and this is what determines how strong or fast something is moving. The more voltage provided, the more performance can be gained from the system, with the ESC actually providing the voltage to the motor.
However, the ESC will always expect a specific amount of voltage coming from the power system and, as such, can only handle a specific amount. Increasing the amount does allow the ESC to respond better but will also cause the ESC to be damaged over time or immediately be shorted.
Not Enough Cooling
Something we have seen many people fail to understand fully is that electrical components can get extremely hot when they are used at max capacity. When your RC car is blasting through the sand or across the road, the ESC and motor are most certainly being used to their full power.
This means that the ESC will become extremely hot, and over time, it will overheat if you have not built in a full cooling solution. This is usually why ESCs come with metal fins attached to certain components to ensure that the machine stays cool as it is being used.
The most common issue for anything burning out on hobby RC cars is something went wrong with the wiring. Even just one small cable connected to the wrong point or plug can cause a system-wide short circuit that can break most of the parts in it.
If your ESC is constantly being shorted when you connect power, you need to take a step back and ensure that all the cables in the RC car have been connected properly. We have seen several people that insist that everything is perfect only to end up later with a shocked look when it is revealed a cable is connected to the wrong socket.
Too much Draw
We don’t see this often as most ESCs can handle much more than the motors connected to their needs. However, in a few rare cases, the ESC will overheat no matter what when the motor connected to it requires too much power to operate properly.
The best way to explain this is like connecting a toy ECS to your hobby-level RC car motor; the ECS will instantly start overheating. It is not created to withstand that level of power flowing through it, with many ESCs having safety systems to melt or break entirely when reaching capacity.
If all you are ever doing is racing your RC car around the track, then this may never be an issue; however, for those who like to play, it can be a real issue. The ESC and many of the other components of the vehicle are not completely waterproof and need to be made waterproof.
This means that when they are driving through sand, rushing across the water, or just playing in puddles out in the street, they can get dirty. As they get dirtier, the ECS will naturally start to short circuit and become useless, requiring a replacement.
Something that we have seen even hobbyist RC car owners doubting is the possibility of reverse voltage from the motor. This is when the wheels are turned on the RC car, and the motor produces a voltage that goes through the system that can and will cause many of the electric components to be shorted.
We have seen many people doubt this, with most RC cars having a system to stop this from causing any damage to the internals. However, when quickly pushed across the ground or just with older motors, the chances of this happening increase greatly, and the ESC is the first part to be damaged.
Why Do RC Motors Burn Up?
ESCs can burn up for many reasons; however, they are made quite robust specifically to not just burn up. As robust as they are, Motors are usually the first components of your RC car to burn up as they are constantly used and abused when using your RC car.
With many motors having one or two lines that are unprotected, should there be a short circuit somewhere else in the RC car. Whether this is on the front servos or on the ESC that controls its direct voltage ratings, understanding the simple but devastating reasons it may burn up is important.
When we are talking about timing for an electric motor, it is a combination of the timing of the voltage being delivered to it and the actual timing of the motor itself. These are both affected by other components of the RC car, and if they are not correct, the motor will not be running correctly.
Incorrect timing can be hard to measure or predict, as the motor will still work and continue to move and provide power. However, the motor may overheat or completely blow up as you continue to use it, which is why you need to measure the motor and test it when you have made changes to the car.
As amazing as it can be to rev your little RC car and to show others the total power that it can deliver, you will need to be careful. Not only will revving cause the electric components to heat up without cool air to cool them down, but the motor will also overheat, short circuit, and blow up.
More common with brushless motors, you will need to ensure that you are not revving your RC car for no reason, especially when you can see that the car cannot move. If the RC car is revving, it will be hurt; the motor and other electronic components are not made to withstand that.
Too Much Heat
This is something we see when people build their dream cars into fully functional RC cars that they can drive over mountains. With the electric motor completely closed off in one section of the car and unable to breathe at all, with the only air inside the motor being the air it was built with.
RC car motors need fresh air to cool down and continue to work properly, and they can only be run for a limited time before just overheating. If you want your RC car motor never to be damaged by the heat that it is producing, we recommend that you ensure that the RC car motor always has fresh air.
Too Much Speed
It may seem impossible or nonsensical, but if your motor is spinning too fast, several things inside it can go wrong and be misaligned. With the magnets losing balance, the bearing breaking outright, and the wiring sometimes becoming damaged as well.
It is understandable to adjust the motor and voltage of your RC car to get more speed and control from it. However, your motor will have set limits that it can safely handle that you will need to adhere to, ensuring that you are not pushing the motor far beyond what it has been made to handle.
We have seen so many people put their foot on the back of an RC car to hold it in place, push the throttle to full, and then enjoy the launch from the little car. However, this damages almost every component of the car that ensures movement, including the motor forwards.
This overheats the motor, damages the ECS and causes the power throughout the system to be overvaulted. At first, this may not cause any issues; however, once done two or more times, you will experience a loss of performance; eventually, the motor will completely burn up and require replacement.
Over Amping of the motor will only happen during a short of the power system or a complete failure of the power supply of your RC car. Whether this happens because of the ECS failing, wires touching, or water getting into the wrong spots does not matter; the results are the same.
Your motor will have most of its circuitry fried, with the motor no longer working at all or, in the worst cases becoming dangerous to operate. When the amperage is too much, your entire RC car may become dangerous enough to kill you if you touch it while delivering power.
What Happens When an RC Motor Overheats?
It will depend on why the motor is overheating; if it is from too much power, then the circuitry inside the motor will be fried, with the magnets also being damaged. However, if the motor is overheating because of no ventilation, then parts of it may start to melt, and the motor may be locked into place.
Some RC car motors have bearings that are heat sensitive and will start to melt as the motor is being pushed far beyond the limits of what it can handle. We have seen several people that do not quite understand their RC cars burning up and will be confused when after everything is replaced, the motor still does not work.
If your motor has overheated, it usually means that you will need to replace everything inside the car as several things have gone wrong. You will also need to ensure that you are not treating the RC car as a cheap electric car; the components deliver much more power and can be easily damaged.
Is It Normal for An ESC to Get Hot?
Yes, as your ESC is constantly controlling the amount of power delivered to most of the parts inside the RC car, it will become hotter when used. Most ESCs will have cooling fins to prevent the part from completely melting or reaching falling temperatures.
If you are repairing or changing parts on the ESC, we recommend ensuring that you have the right cooling installed back onto it. If you decide not to install the fins again, you will most likely have the ESC completely fail when it is trying to work as the components cannot handle the heat.
Further, we recommend placing the ESC somewhere that it is constantly cooled by air moving over and through the car. This ensures that the components are completely cooled without having to stress about the components baking in their heat all the time.
Your ESC and the motor of your car can easily overheat if they are being overvaulted or being mistreated. You need to ensure that the components are not being completely abused and that the car can provide cool air when it is moving without having the body completely sealed.
Whatever you do, please don’t pull the throttle at full speed and then almost stand on the car; nothing would ever want to feel that!