ESC faults are one of the most common issues faced by FPV drone pilots. ESCs are common areas of fault, often receiving the most abuse and continued strain of any electronic in the RC object. In this guide, we will discuss common ESC faults and ESC troubleshooting, including ESC burnout, desync, and firmware corruption.
For those looking to better understand ESCs and how to select the right one for their FPV drone, check out this comprehensive guide on How to Choose the drone ESC.
Fault 1: Understanding ESC Burnout and Prevention Tips
This is by far the most common issue experienced with ESCs. Most of the time ESCs are bulletproof and connected to the FC, which allows for minimal tampering on the firmware side of things, allowing for low anomalies in the typical use cases.
Unfortunately, they are not indestructible and thus large crashes, excessive stress or overvoltage may occur. This is physical damage to the ESC and is unfortunately very rarely fixable and when it is, it requires micro soldering skills to replace the damaged component, writing it off as its never worth it unless the part is discontinued and essential.
Some physical cues of this problem would be:
- Physical chips or cracks in the board.
- Black soot near pads and components indicating a burnt board.
- Missing components and empty micro pads.
- Other forms of internal damage that may not be visible.
There are currently no real fixes to this issue and if you rule out all other forms of problems shown later in this article, this might be it.
Fault 2: ESC Desync
This is another common issue when it comes to 4 in 1 ESCs. This occurs when the motor and ESC timings do not line up. You can diagnose desync through the way the FPV drone acts in the air or on the ground.
Sometimes it may spasm and fall out of the sky or spool up on the ground. When one of the motors stalls (ceases spinning and thus stops providing thrust), the drone commands that motor to spin harder, which causes the motor signal to reach its maximum of 100%. All of these are easily solvable through the ESC configurator.
What Causes ESC Desync?
- BetaFlight: Some common causes of this issue are too high KV motors, ESC overload
- Software Issues: Normally the motors that are too high in KV can be solved by limiting the motor output through BetaFlight.
Some physical cues of this problem would be:
- FPV drone flipping erratically out of the sky.
- FPV drone spooling up and then ramping power up rapidly to one or motors.
Not all issues like this are ESC Desync. They can be a range of things from burnt out components to faulty motors to an overheating ESC. This means that the only real way to diagnose ESC Desync is through Blackbox logs on BetaFlight or KISS.
How to Fix ESC Desync Issues Using BetaFlight?
There are multiple fixes to this ESC fault, stemming from the Flight stack most of the time.
Option 1: BLHeli
- The first course of action would be to go into BLHeli and review the ramp-up power of the FPV drone, setting the value to 0.125 in BL HeliS and 12% in BL Heli 32/ AM 32.
- A last course of action for those who get the quad in the air but experience issues there would be to set the damage compensation to high, albeit at the cost of some performance.
Option 2: BetaFlight
- Go into BetaFlight and use a Dshot ESC protocol is not already being used.
- Set motor idle throttle value: Normally slightly in the weaker range for smaller quads so setting it to 6 or 7.5% would help get those motors spun up.
You can also read the ours detail guide to fix FPV desync issue.
Fault 3: Motor Stuttering or Refusing to Rotate
This is one of the more vaguer issues that plague our FPV drones and ESCs. It can be caused by a variety of things, all ranging between mild and severe magnitude. One issue is not even caused by the ESC, but rather the joints being soldered to it.
Make sure that NONE of them are bridged, as this can not only cause the motor to stutter and eventually burn out, but can even cause a fire if the ESC bursts under pressure.
Another would be to check the wires for under sheath cracks, which are invisible points of failure. This is one of the more difficult issues to find, and the way I have done it (although not recommended) is to pull on each individual wire (NOT FROM ONE END PUTTING ALL THE STRAIN ON THE ESC, BY PULLING THE WIRE FROM BOTH ENDS EQUALLY) and observe any stretches in the wire.
Another thing I would do is check my ESC calibration on BetaFlight and that all the motors are rotating in the right direction. To do this, go in the motors tab on BetaFlight and test each motor individually.
Some physical cues of this problem would be:
- Hot motors due to the constant current change.
- Erratic motor movement.
- No motor movement on one or more motors.
- Loose or damaged wires.
- Clicking or grindingesque noises.
- Warning on FC or ESC Rapid beeping.
Drone Motor Stuttering Troubleshooting
There are also multiple ways to diagnose and resolve this problem:
Option 1: Joimts and Components
- Check that all the wires are soldered on correctly and none are loose
- Make sure that none of the wires or joints are shorting, either on the components or the carbon fibre.
- Use a multi-meter to check continuity between motors and FC.
Option 2: Check ESC Faults Related to Motor Stuttering
- Switch the motor to another ESC Channel and see if that works. If it does, there is a major problem with one of the ESCs on the PCB.
- Replace damaged ESC or try re-flashing firmware.
Fault 4: ESC Does Not Power Up
This is a far more centralized issue compared to the others, with there only being a couple of diagnosable issues. Either there is an issue with your power supply (battery, battery leads, etc.), a problem with your soldered joints to your ESC, a short circuit, and a burnt ESC.
Some physical cues of this problem would be:
- No response or beep from the ESC after battery is plugged in.
- No power to the FC or rest of the drone.
- Error code or rapid beeping from the ESC.
Troubleshooting for ESC Power Issues
There are a few remedies, but they may not work if the ESC is Physically damaged:
Option 1: Physical Check
- One thing that can be conducted is a quick look over and evaluation of the component, checking for broken joints, physically burnt components and if anything at allis being exhibited from the ESC when plugged in, even a small led.
Option 2: Replace
- This is something every pilot dreads, the day their expensive board dies. It’s not all bad though, with boards becoming cheaper and cheaper.
Fault 5: ESC Firmware Corruption (Bricked)
This is one of the most common problems and it occurs when an ESC without an update failsafe (mostly cheaper ESCs). It normally only occurs when the update is interrupted, but may also occur due to firmware release candidates causing a brick. There is a fix for this though, and it’s probably the simplest.
Some physical cues of this problem would be:
- Error blinking light and beeping.
- No power to FC but ESC powered on.
How to Fix ESC Firmware Corruption?
This is the easiest issue to fix, simply
- Reflash the firmware to the ESC, this time making sure nothing happens during its update if the ESC was bricked by an update interruption.
- Flash the ESC with a slightly older firmware if it was caused by a release candidate.
Fault 6: One of the Main ESC Faults – Noise Interference.
This is the most common and easily fixable fault that everyone will experience at least once in their lives as FPV pilots. It occurs when there is too much electrical noise, often caused by the wrong filter settings or vibrations. Fortunately, this is also a fix that can be easily implemented in a build.
Some physical cues of this problem would be:
- Jittery flight characteristics.
- Randomly overloading the quad and bottoming out into the ground.
- Far lower power.
- If analog, wavy electronic interference in picture due to murky power supply through ESC.
How to Fix Noise Interference in ESCs?
This is an easily rectifiable ESC issue:
Option 1: Physical Fixes
- Add a capacitor the right size for your ESC. Often, boards under 2s will have built in capacitors/resistors but above that, capacitors are very handy. To find the right size capacitor, I recommend finding ESCs and stacks with ESCs included and seeing what size they are.
Option 2: BetaFlight Settings
- Go to Betaflight and adjust your filters. If you have never touched or seen filters, look for a preset, download the preset and then manually change your rates back to what they were, keeping all other settings. For 5-inch FPV drones for example, the SupaFly preset is by far the most popular and often the start of a pilot’s own bespoke tune.
This was a comprehensive guide to common ESC faults and troubleshooting advice. Today, ESCs have come further than ever imagined, and need some diligent care and maintenance. They may have their days, but they can last through thousands of crashes. This article aims to educate and help you get your FPV drone back in the air as fast as possible.
By following this guide, you will be able to troubleshoot common ESC faults and ensure your FPV drone performs at its best. I hope this helped!