Hot motors are one of the most common issues in FPV drones. They are warning signs that something isn’t right with your quad, sometimes accompanied by trilling oscillations and vibration. While warm motors after an intense flight are normal, excessively hot motors can lead to reduced performance, damaged motors, and even a mid-flight crash. In this article, I’ll explain why FPV motors get hot, what typically causes it, and how to fix it.
Why Are Hot Motors Bad?
- Hot motors lead to hot magnets, which can cause demagnetization and reduce motor efficiency and power.
- Some types of magnets may have better heat resistance than others, but magnets can still lose magnetic strength over time due to constant overheating.
- When motors get too hot, the enamel coating on the motor windings can melt, causing electrical shorts inside the motor and permanently damaging it.
- Energy is also wasted as heat, which results in shorter flight time.
How to Tell if Your Motors Are Too Hot
Pinch the motor bell with your fingertips after a flight. If you can’t hold your fingers there comfortably for more than a few seconds, the motors are too hot.
Why Motors Get Hot
At a high level, motors heat up when electrical energy is not efficiently converted into mechanical motion.
- If the motor spins freely: electrical energy → kinetic energy → minimal heat
- If the motor is resisted or forced to fight itself: electrical energy → heat
So in real flight, when the motors appear to be spinning normally, why do they still overheat?
Modern flight controllers constantly adjust motor RPM to stabilize the drone. Ideally, those adjustments are smooth and stay within what the motor can physically achieve. But when commands change faster than the motor can respond, problems occur.
Motors have mass and inertia, which means they cannot instantly speed up or slow down. If the flight controller sends extremely rapid changes, the motor ends up fighting those commands.
The result:
- Current surges back and forth through the windings
- Energy is dissipated as heat instead of motion
- Motor temperature rises
- Internal electromagnetic losses increase
Even though the motor appears to be spinning normally, it may actually be under a lot of internal stress.
Too Much D-Term, Too Little Filtering, or Both
While many factors can contribute to hot motors, suboptimal PID tuning and filter tuning are probably one of the most common causes in FPV drones.
Not sure what PID is? Check out this beginner’s guide: https://oscarliang.com/pid/
D term is essential for smooth flight. It helps dampen overshoot and reduce prop wash. But it is also one of the primary causes of motor overheating. You want just enough D gain to get good flight performance, but not too much that it creates excessive noise and heat. That is why proper PID tuning is important.
I have a whole blog post that explains this in more detail here: https://oscarliang.com/excessive-d-gain-cause-oscillations-motor-overheat/
In a nutshell, D-term amplifies high-frequency signals. This is useful for damping oscillations, but it also amplifies noise. If noisy gyro data enters the PID loop, D-term boosts it and sends those rapid fluctuations to the motors, and it becomes a feedback loop which makes the problem worse. The motors then receive commands they physically cannot follow.
Result: heat.
The general approach should be:
- Configure filtering properly first, to minimize latency while sufficiently reduce noise before it reaches the D-term calculation
- Use appropriate amoutn of D-term filter settings
- Increase PID gains only until it starts becoming too noisy
- If you don’t know what you are doing, just stick with Betaflight default
Here are the tutorials explaining how to tune PID and filters:
How to Fix or Prevent Hot Motors
To diagnose the issue, perform similar short test flights. Make sure you fly the same path and use roughly the same throttle in every test, so the comparison is meaningful.
30 seconds to 1 minute at 50% to 70% throttle is a good starting point.
New Propellers
The first step in troubleshooting hot motors is to change the props. Sometimes the blades may be bent and it is not very obvious. If you have previously had successful flights with a particular type of propeller, start there. Make sure you are not using propellers that are too large or have a pitch that is too high, as this can put excessive load on the motors.
Inspect and Secure All Components
The next thing to check is how securely all the components are mounted and whether all screws are properly fastened. Make sure the frame, camera, and FC stack are all secure and that there are no loose screws. At the same time, do not over-tighten the FC stack nuts — leave a little room for the soft mounting to do its job.
Also make sure there are no dangling wires that could potentially hit the FC or gyro during flight, causing vibrations. Secure all wires with zip ties.
Check the Motors
Are the motor screws touching the motor windings because they are too long? How to check: https://oscarliang.com/check-motor-screws-touching-winding/
Then proceed to open the Motors tab in Betaflight Configurator. Remove all propellers first, plug in battery, then spin each motor and look for differences by checking the gyro traces in the configurator. This can help you determine whether a particular motor is noisier and causing more vibration than the others.
It is also possible that one motor is faulty. For example:
- the bearing may be worn out or damaged
- the motor bell / magnets may be scraping the stator due to a bent shaft
- the motor bell may be unbalanced
48kHz ESC PWM Frequency
Using 48kHz PWM frequency in your ESC settings may reduce braking power slightly, but it can make motors run smoother and reduce motor heat.
Using AM32 ESC? Here are my recommendation settings: https://oscarliang.com/best-am32-settings/
Use More Conservative PID and Filter Tunes
An aggressive tune with too little filtering often leads to scorching motors. If you start getting hot motors after changing PID or filter settings, you should roll those settings back.
The default settings in Betaflight are fairly conservative and generally work well across a wide range of models. You should not normally get excessive oscillations or hot motors with the stock tune, at least on 5-inch and smaller quads anyway. Once you have confirmed that the default tune does not produce hot motors, you can begin tuning more aggressively, one setting at a time.
The key questions are:
- Is D gain too high?
- Did you reduce filtering too much?
If you are still getting hot motors with the default PID and filter settings, that is a strong sign the problem may be mechanical, such as poor build quality or a faulty component.
Add More Capacitors
If you do not have a capacitor soldered to the ESC power pads yet, you should.
If you already have one, try using a larger capacitor or adding an extra one for more capacitance. This may help reduce electrical noise reaching the gyro, which can contribute to vibrations and unstable motor behavior.
Capacitors are never too many, as long as you have the space for it.
I have a tutorial explaining why, what and where you should use capacitors: https://oscarliang.com/capacitors-mini-quad/
Final Thoughts
A well-performing quad should fly smoothly, efficiently, and land with motors that are cool or only slightly warm — not scorching hot. Whenever electrical energy is not efficiently converted into motion, it becomes heat. The cause can be hardware-related or software-related, so you need to work through a checklist to find the real source of the problem.
Either way, a hot motor is bad. It hurts performance, can damage the motors, and may even lead to failures in flight. That is why it is important to regularly monitor motor temperature and address hot motors before they become a bigger issue.
Edit History
- Feb 2023 – Guide created
- May 2026 – Updated
