ODrive Pro reports 4.8–5.4 V for vbus_voltage despite measuring 24 V at DC+ and DC−

[William]

I’m troubleshooting an issue with my ODrive Pro where the reported DC bus voltage does not match the voltage measured directly at the power terminals. I’m hoping to identify the cause and determine whether this is a hardware issue or something that can be fixed.

Symptoms

My ODrive Pro is supplied with 24 V DC, measured directly across the DC+ and DC− solder joints using a multimeter. The measured voltage is 24 V, but vbus_voltage in the ODrive GUI consistently reports approximately 4.8–5.4 V. The controller consequently triggers an active DC_BUS_UNDER_VOLTAGE error. The undervoltage trip threshold is set to its default value of 10.5 V.

The wiring and measurement points have been verified, and this setup previously worked correctly.

Troubleshooting performed

• Verified the power supply voltage: I measured 24 V directly across the ODrive Pro’s DC+ and DC− power terminals while observing vbus_voltage in the GUI at the same time.
• Compared GUI and UART readings: I previously read vbus_voltage through UART using an ESP32. It reported the same incorrect value as the GUI, suggesting that this is not simply a GUI display issue.
• Tested with only USB-C connected: I disconnected the 24 V supply and all other system connections, leaving only the computer connected to the ODrive through USB-C via a ground-loop isolator. In this state, I measured 0.949 V across DC+ and DC−, while vbus_voltage continued to report approximately 4.8–5.4 V.
• Updated the firmware repeatedly: Updating through the GUI did not resolve the issue.
• Reinstalled the firmware through legacy DFU: I successfully used odrivetool legacy-dfu to reinstall firmware version 0.6.12-1, explicitly selecting ODrive Pro. The incorrect voltage reading persisted after the reinstall.

Current assessment

Since the discrepancy persists after reinstalling the firmware, I suspect a possible problem with the DC bus voltage sensing circuit, its connection to the ADC, or another part of the measurement chain. However, I have not yet confirmed the root cause.

I’m particularly interested in determining whether this is a known issue with the ODrive Pro and how to diagnose it at the hardware level. I would appreciate guidance on locating the DC bus voltage sensing circuit, identifying the relevant test points or components, and checking whether the fault is in the sensing circuit or the ADC measurement path.

If this points to a hardware defect, I’d also appreciate advice on repair options.

Thank you for your help!

[solomondg]

Hi! Thanks for reaching out, and for the detailed description. Not a known defect, it does sound like a possible hardware issue. Did the Pro have this issue out of the box, or did it happen after some use? Could you send some pictures of the top/bottom of the board?

[William]

Hi! Thanks for the reply. I’ve attached pictures of both the top and bottom of the board.

The ODrive Pro had been working correctly before the issue occurred. We were running it at 24 V with a velocity setpoint of 1 rev/s. We were performing tests, and at one point, when we started another test after modifying our ESP32 code, the DC_BUS_UNDER_VOLTAGE error appeared. We’re not entirely sure what caused it, as we didn’t make any intentional changes to the power supply or motor command that should have damaged the drive.

We were using a regen clamp with a 50 W, 2 Ω resistor. At the time the issue appeared, the drive was operating at only 24 V and 1 rev/s, so we wouldn’t expect these operating conditions to have caused a component to fail. There was no unusual smell, visible damage, or other obvious sign of a hardware failure.

To help isolate the issue, we are currently running the same system with an ODrive S1 as a temporary replacement. The S1 correctly measures the DC bus voltage, and the rest of our circuit works as expected. However, the S1 limits our motor’s performance, which is why we would like to get the Pro working again.