PX4 Voltage Spikes

We’re running into an issue with what we think is the cubepilot mistakenly reading voltage spikes. This started when I was flying the drone back and it just dropped out of the sky from around 30ft. Earlier in the day, we were getting voltage spike warnings and you can see in the log under the power section that the voltage is a lot more volatile than normal (going from 14.8V up to 15.6V in less than a second). We tried swapping out the power module and did not see any change in volatility. We have another pixhawk 6c running the same firmware / parameters with the same power module and we’re not seeing these big swings in voltage measurements. We’re wondering if you’ve seen this issue or if it could mean some portion of the board is fried.

Here’s the log:
Flight Review - Quadrotor (px4.io)

I think it’s unlikely that noisy voltage readings or the sudden loss of power has to do with the Cube. I’ve seen loose wiring cause the current/voltage readings to act strangely many times, but never the flight controller itself. And never discount the chance that the readings are real - did you try another battery? An unhealthy battery with high resistance or a weak cell will absolutely have volatile voltage while under variable load.

As for the power loss, I am suspicious of your power system readings, but I also don’t know what is normal for your system. A multirotor flying on a mere 4 amps is unusual, and the battery remaining estimation does not make sense to me (but I don’t know how PX4’s estimator works). The sudden drop in battery remaining without any change in voltage is weird.

That said, my guess is that it is a red herring. A sudden power loss is almost certainly a problem with your power system hardware. If you are using a carrier board that supports multiple power inputs, double-check that all inputs are reading good throughout the flight (Ardupilot has a power status flags log item for this, not sure about PX4). And of course, check your wires, solders, etc.

Another possibility is software, I suppose. I’m not sure if PX4 has a watchdog or other crash recovery/diagnostic process, but if it does, it could provide clues.