Voxl ESC not responding and not detected

Jetson Nano

Hello @Vinny @Eric-Katzfey @Alex-Kushleyev @modaltb

I am facing an error with my Voxl FPV ESC. The ESC is not responding to any command. While plug in power the ESC is only blinking 3 LED for the initialization, then there is no LED blinking.
The ESC was working fine, during a flight test the motor suddenly stopped and the drone was landed safely somehow, but after that the motors are not starting, there are no visible damages.
I am attaching the terminal results, I tried to upgrade the firmware, alchange the parameter file, but the ESC is not responding. I also checked with various baudrate, the result is same, no response.

:~/Downloads/voxl-esc-master/voxl-esc-tools$ sudo python3 voxl-esc-scan.py
Detected Python version : 3.10.12 (main, Mar  3 2026, 11:56:32) [GCC 11.4.0]
Found voxl-esc tools bin version: 1.10
INFO: All COM ports:
	/dev/ttyUSB0 : FT232R USB UART - FT232R USB UART
INFO: UART Port Candidates:
	/dev/ttyUSB0
INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 2000000
INFO: Scanning for ESC bootloader: /dev/ttyUSB0, baud: 230400
WARNING: No ESC(s) detected
INFO: All COM ports:
	/dev/ttyUSB0 : FT232R USB UART - FT232R USB UART
INFO: UART Port Candidates:
	/dev/ttyUSB0
INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 250000
INFO: Scanning for ESC bootloader: /dev/ttyUSB0, baud: 230400
WARNING: No ESC(s) detected
INFO: All COM ports:
	/dev/ttyUSB0 : FT232R USB UART - FT232R USB UART
INFO: UART Port Candidates:
	/dev/ttyUSB0
INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 921600
INFO: Scanning for ESC bootloader: /dev/ttyUSB0, baud: 230400
WARNING: No ESC(s) detected
INFO: All COM ports:
	/dev/ttyUSB0 : FT232R USB UART - FT232R USB UART
INFO: UART Port Candidates:
	/dev/ttyUSB0
INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 57600
INFO: Scanning for ESC bootloader: /dev/ttyUSB0, baud: 230400
WARNING: No ESC(s) detected

ERROR: not all ESCs found

please help me out here, is there any way to figure out why is this happening and how to solve it, I had a similar instance earlier, but the ESC was responsive and one motor was glitching. it was stopping during rotation. changing motor did not help, so i changed the ESC and it worked.

what I do to maintain the ESC safety and working.

Jetson Nano

@Vinny @Eric-Katzfey @Alex-Kushleyev @modaltb
Hi Guys,
Any update would be great appreciated.

Alex Kushleyev

@Jetson-Nano ,

In a case like this, if the ESC works and suddenly stops working, the resulting state is probably a hardware problem (possibly caused by software action or hardware damage). In this state, it is probably impossible to recover the ESC using software and remote diagnostics would be difficult and you would probably not be able to fix the ESC hardware anyway.

Do you have any additional information that could help us understand what happened and the frequency of occurrence? you mentioned two occurrences "recently" -- any more details? What motor/prop/battery was used and was there anything unusual that happened during the test? Do you have a px4 log from the flight? (you could share it privately if needed).

If you are able to ship two failed ESC boards back to us for investigation, i'll ask our team if we can send you new replacement(s).

Alex

Jetson Nano

Hello @Alex-Kushleyev ,

Thank you for getting back to us.

Please find below a detailed summary of the failure scenarios observed during our recent flight testing activities. We would appreciate your assistance in analyzing these events and identifying any potential root causes.

System Configuration

VOXL 2 → Flight Controller V2 → ESC
Motor: T-Motor F60 Pro LV, 2020KV
Propeller: 5-inch Three-Blade Propeller
Battery: 6S, 5000mAh (21700 Cells)

Scenario 1 – VOXL FPV ESC Failure

During flight, the drone was operating normally when the rear-left motor suddenly stopped, causing the aircraft to lose stability and topple.

Following a system reboot, the affected motor exhibited abnormal behavior:

The motor would begin rotating briefly.
It would then stop unexpectedly.
This cycle would continuously repeat.

The same behavior was reproduced while running the ESC spin.py test utility.

As part of troubleshooting, we:

Updated the ESC firmware to the latest available version.
Applied the recommended parameter changes.
Repeated motor and ESC validation tests.

However, the issue persisted, and no improvement was observed.

Scenario 2 – VOXL FPV ESC No Longer Initializes

In a separate flight test using a replacement ESC, the drone was in a stable hover when the front-left motor stopped unexpectedly, causing the aircraft to topple.

Following the incident:

The affected ESC no longer initializes correctly.
During power-up, the ESC LEDs briefly illuminate and then turn off.
The ESC does not appear to complete its startup sequence.

Troubleshooting performed:

Connected the ESC directly to a computer.
Attempted to establish communication and detect the ESC.
Performed multiple power cycles and reconnection attempts.

Unfortunately, the ESC could not be detected, and communication could not be established. The terminal output associated with this issue was shared previously in our earlier correspondence.

Scenario 3 – Third-Party ESC Evaluation

To further isolate the issue, we replaced the VOXL FPV ESC with a NeutronRC X-CLASS 4IN1 ESC V2 (3–8S, 70A) configured using the DShot protocol.

During testing, we observed the following:

ESC temperature increased rapidly, reaching approximately 80°C to 90°C within two minutes of flight.
One motor would subsequently stop during flight.
The aircraft would lose stability and crash.
During or immediately after impact, the ESC appeared to reboot.
Following the reboot, the system would operate normally again.

This behavior has been consistently observed across five separate flight tests, with each flight resulting in a similar failure sequence and crash.

Additional Observations

While reviewing the available flight logs, we observed elevated ESC temperatures:

General ESC operating temperature ranged between 75°C and 88°C during the affected flights.
ESC(0) reached a peak temperature of approximately 88°C.
During earlier flight tests under similar operating conditions, ESC temperatures typically ranged between 60°C and 75°C.

Installation and Thermal Management Details

The ESC is installed inside a closed enclosure with the following thermal arrangement:

Bottom-mounted aluminum heatsink.
Thermal interface material between the ESC and heatsink.
Side walls constructed from aluminum structural members.

Despite the presence of thermal conduction paths, the elevated temperatures observed during flight raise concerns regarding thermal dissipation and potential thermal shutdown behavior.

Flight Logs

Log File:

https://drive.google.com/file/d/1wxv7VZub4-7onK6YdgcJ8kSpGhpZ40mY/view?usp=sharing

Note: Access approval may be required to view the file. If the link is inaccessible, please send an access request and we will grant permissions immediately.

Given that similar symptoms have been observed across both the VOXL FPV ESC and a third-party ESC platform, we would greatly appreciate your guidance on:

Potential root causes of the motor shutdown events.
Whether the observed temperatures are within acceptable operating limits.
Recommended diagnostics or logging parameters to further isolate the issue.
Any known interactions between the motor, propeller, battery, and ESC configuration that could contribute to these failures.

Please let us know if any additional logs, hardware details, configuration files, or test data are required from our side.

Thank you for your continued support and assistance.

Jetson Nano

@Vinny @Eric-Katzfey @Alex-Kushleyev @modaltb
Hi Guys,
Any update would be great appreciated.

The requested data is provided above.

Alex Kushleyev

@Jetson-Nano ,

Thank you for providing detailed description of the tests. I just requested access to the logs.

Please see the following comments:

ESC temperature: the VOXL FPV ESC is rated for pretty high operating temperatures. For example, the MCUs are rated to run at up to 125C MCU temperature. I would not recommend running the ESC above 100C, however I am confident that the ESC will perform fine even above 100C. We typically recommend designing the system such that ESC temperature does not exceed 80C under normal flight conditions - this gives plenty of margin before a failure would occur. Did you take note of the ESC temps of VOXL ESC?
VOXL FPV ESC reports two types of temperatures: two of the IDs (ID 0, 3) are measuring the ESC temps from separate temperature sensors located on top and bottom of the ESC. IDs 1 and 2 are reporting the MCU temps (the temperature of the MCU silicon). The MCU temps at steady state are typically a bit higher (5-7 deg C higher) because the MCU itself generates a little heat internally.
VOXL ESC not responding after a crash : the likely reason is mechanical damage as a result of the crash. Components can be knocked off during the crash. If the ESC powers on briefly (you see the leds blink initially, but then the ESC turns off), then the likely issue is some kind of short or high load on one of the regulated ESC power rails (5V or 3.3V) -- the high current drain (due to some issue) results in the voltage regulator to turn off due to over-current, resulting in the ESCs shutting down. If only 3 out of 4 LEDs blink, then it is possible that one ESC channel has some sort of a short (due to mechanical damage) and it does not turn on, eventually causing the power rails to be disabled due to over-current.
motor suddenly stopping in flight: this is often a result of a mechanical issue related to mounting the motor to the frame. Sometimes the motor mounting screws are too long and they can penetrate the motor windings and cause intermittent failures just like this. We have experienced this ourselves several times when long screws were used and were touching the motor windings. Alternatively, something could be touching the ESC itself and intermittently affecting operation of the ESC
once I see the px4 log with the FPV ESC, i can check if one of the motors was operating abnormally before it stopped spinning. There is some additional information in the log that can tell us if a particular motor requires more power to spin (compare to the others).

Questions:

do you have px4 logs of the VOXL ESC with one of the motors shutting down in flight?
is it possible that the aluminum enclosure is making contact with the ESC components, causing some kind of short? especially during crash, perhaps the ESC is making contact with the enclosure?
did you check if the motor temperature was OK after successful flights?
what was the total current draw during flight when the failure occurred? (should see that in the px4 log)

Alex