NEED HELP PLEASE motors screaming / cogging under harsh acceleration

Hello! This is going to be a lengthy thread of my build and the issue I have with it along with what I have tried to fix.

I am currently using: 2x 6s 12 Ah Lipos 15c with no BMS (Continuous current limited to 180 A)

6354 140 Kv motors from Flipsky (SENSORLESS OPERATION) (15t - 40t Cloud Wheels 120mm)

Spintend UBOX V2 (Yes the receiver is NOT being blocked or interrupted by power cables in any way)

Flipsky VX2 (Connected via UART)

The link below is a link to all of my settings on the UBOX V2 and a picture of how it sits in its enclosure:

Here is also an audio recording of how it sounds when it cuts out (AUDIO MAY BE LOUD):

Now for the issue, When using my previous controller (Flipsky FSESC 6.6 Plus) I had no issues except sensor issues (Why I refuse to use sensors period since it threw me off), but when switching to the Spintend UBOX V2 the motors seem to almost scream and cog when under harsh load (Full throttle accelerating) and throw me off balance (as heard in audio). They spin up to max just fine under no load and as seen in the settings folder no faults are detected or thrown when it occurs. I have contacted Spintend about the issue and they have said that it is a compatibility issue and to play with the FOC Switching Frequency. I tried switching from the original (40kHz) to 25kHz (My original that worked on the FSESC) then to 20kHz and then to 24kHz. Switching to 25kHz gave me the best results but still cut out around 26MPH on flat surfaces and then even slower on hills. When I reported that I’ve had no success they suggested messing with the settings: Sample in V0 and V7, Current Controller Decoupling, and Observer Type. I have not messed with these settings as I am still unknowledgeable of what they do and don’t want to change a setting without knowing what it exactly does. Spintend has reported no issue with Flipsky 6384 motors (not specified which kV though) and I already planned on switching to those (6384 190kV) in about a month when I have enough money but I want to use the controller now while I have it. Now for my questions:

Should I keep trying to play with the Switching Frequency until it works? The only reason I haven’t yet is that I don’t want to ride it up to 30MPH only for it to cut out then as the issue only comes up when a load is present.

What are these settings and what do they do exactly: Sample in V0 and V7, Current Controller Decoupling, and Observer Type?

Help would be extremely appreciated here as I want to get this controller working with my current setup and hopefully, no problems come up when I switch to 6384 190kV motors or when I reach 30+ when using the 6354 motors.

Question as I’m looking at the set up, I heard the audio, but what did you mean by “cut out”? As in the motors stops on its own? Or the remote no longer registers?

And another question. Did you try the normal foc set up and see if the problem still persisted? Normally these two would help get things solved quicker. I’ve only had a similar issue due to the remote. But it seems like something else here.

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The motors stop and freak out on their own. Remote signal not interrupted at all. I tried both automatic and manual setup for FOC. I haven’t tried BLDC yet.

Hmm. I’ll look more into this.

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Thank you. :slight_smile:

Actually quick question, have you tried changing your battery current max and regen? I feel like that could be a factor since 15c is extremely low for an esk8.

I would test that.

The batteries are 12ah so the max power draw continuously is 180amps. I have it set to around 100 and then -13.

I would test it to be safe. Sometimes its not always the settings. If it still acts up with a lower setting, I’ll see if there’s anything else.

I have forgotten to mention that I have tried at 70 as well. No faults were thrown on these values though and why would it work with an Fsesc 6.6 plus vs a Spintend UBOX V2 the ubox should be far more capable.

Alright. I’ll see if there’s more info. So far, only the v1 is spoken about.

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Thanks. Yeah I’ve noticed that but even then there hasn’t been much conversation on these controllers in general.

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Check for good contact of phase connects. Mine did some of that when bad connection.

I did check them as well there are no issues. I know for a fact it’s not the phase connections because the board cuts out earlier depending on the switching frequency. At 40 kHz it would cut out at around 10mph instead of the 26. I’m using MR60 connectors too that work just fine on the other controller with the motors.