Why FPV Drone Having Jello, Vibrations issues, and Motors Getting Hot? Troubleshooting Guide

If you’ve been flying your FPV drone and suddenly experienced vibrations, jello, or even hot motors, this tutorial is for you. I’ll break down the potential causes and share some tips to troubleshoot shakes and motor overheating issues.

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New Propellers

The first step in troubleshooting is changing the props. Why? Because they are the cheapest and easiest to replace. If you’ve had successful flights with a particular type of prop, start there. Replace them with new ones and test again. Sometimes, the issue can be resolved as easily as this.

Secure All Components

The next thing to look at is how securely the components are mounted. Make sure that the frame, camera, and FC board are all tight and secure.

Believe it or not, your drone might be flying perfectly fine, it might be having jello in your goggles simply because of a loose camera. And a loose frame or flight controller can cause the drone to vibrate because they can make gyro data more noisy.

If the components are secure but you’re still experiencing shakes, check your frame and the wiring. Make sure that no wires are touching the gyro or the flight controller, as these can lead to shakes mid-flight. I have found that even a loose antenna can cause sudden wobbling.

Checking Motors

To check your motors, head over to Betaflight Configurator and go to the Motors tab. After removing all the props, spin each motor and look for variations by checking the Gyro traces in the Configurator. This will help you understand if a particular motor is particularly more noisy and causing the jello.

Checking ESC

Try to redo all your motor to ESC soldering.

If you are still having issues with a particular motor, consider swapping two of the motors (so they are connected to a different ESC), and see if the same motor still having issue, so you can rule out if it’s an ESC or motor related issue.

Also try setting PWM frequency to 48KHz in BLHeli settings which should give you smoother performance than lower settings.

Why Hot Motor is Bad?

• Motors can burn if they get too hot, the coating on the winding can melt and cause electrical shorts inside the motor, smoke will come out and it’s permanent damage to the motor
• Constantly overheating motors can have an impact on performance in the long run as the magnets lose magnetic strength; Some types of magnet might have higher heat resistance than others
• More energy is wasted as heat, results in shorter flight time

It’s normal that motors on an FPV drone get warm after an intense flight, but how hot is too hot? An easy way to tell is to pinch the motor by the bell with your fingertips, ideally right after landing. If you can hold your fingers there for more than 10 seconds comfortably, then it’s fine. If it’s too hot to hold, then it might be a sign of overheating.

The Causes of Hot Motors

Your motors will get hot after some aggressive flying. To properly diagnose the issue you should fly at a slower pace e.g. 40% to 70% throttle is a good starting point, and one or two flips and rolls here and there are fine.

Motor Bolts Too Long

With hot motors, the very first thing I’d check would be if your motor screws are touching the windings.

PID Tuning and Filter Settings

PID and Filter tuning in Betaflight can be a rabbit hole. If you are getting hot motors after changing PID and filter settings in Betaflight, you should go back on these settings.

Default settings in Betaflight is known to be conservative and generally work well on a wide range of models to avoid oscillations and hot motors. Once you’ve made sure you don’t get hot motors anymore, you can start tuning it more aggressively, one setting at a time. Important points are:

• Is D Term too high? (why can high D gain cause oscillations?)
• Did you reduce filtering too much?

If you are still getting hot motors with default PID and filter settings, then that’s an indication that the problem might be mechanical – e.g. bad components or low build quality.

Mechanical Problem?

Maybe something isn’t done properly with the build.

• Make sure all the screws are tight (frame and motors)
• Are all the arms stiff and rigid?
• FC is installed snugly and doesn’t move (nylon screws and standoffs in the stack)

FC Soft-Mounting

If you are not soft-mounting the FC, then you should! As long as you are soft mounting the FC properly, you don’t need to worry about soft mounting the motors.

Adding More Capacitors!

Adding extra capacitors to the ESC power or XT60 pads, will help reduce the amount of noise in your power. Thus reducing the noise in the gyro data too!

Center of Gravity

If two of the motors are hotter than the others, it could be caused by unbalanced weight distribution. If your quad is front heavy, or tail heavy, two of the motors will have to work harder and therefore get hotter. Make sure the COG is right in the center for the best possible performance.

Motor or Propeller Jammed

Make sure the propellers are not hitting anything on your frame (battery strap, zip tie, standoffs etc), and that the motors are not getting jammed by dirt or grass… If this is the case you should usually hear it when the motors are spinning.

Also make sure the props are not bent. It’s quite hard to tell visually sometimes, change them out if in doubt.

Faulty Motor?

It’s possible that you have one or multiple faulty motors. Maybe the bearing is bad, or the motor bell is scraping the stator due to bent shaft, or a unbalanced motor bell…

If you have one motor that is hotter than the rest, and nothing mentioned above helped, try swapping around the problematic motor with a fine motor on the same quad, see if that’s still the issue with that motor.

It’s Too Hot Outside?

Take into account the ambient temperature outside, your motors will have a harder to time to cool down on a hot day. Black motors will be affected even more when you are flying under the sun.

If this is the case, try again under the shade or in the evening.

Conclusion

Drone troubleshooting can be a daunting task, but with systematic analysis and a bit of hands-on tinkering, you can resolve most issues. Whether it’s shakes, jello, or hot motors, the solutions are often easier than you think. So, don’t be afraid to get your hands dirty; a smoother, more reliable flight experience is well within your grasp. If you need further assistance or wanna share your experience, visit our forum, IntoFPV.com

Edit History

• May 2019 – tutorial created
• Feb 2023 – updated