VESC high kv issues and BLDC detection

Esk8 Electronics Guides, Support, & General Questions
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I just blew up one of my Makerx Hi100 controllers trying to get 300kv motors running with 12S. Was working sweet on 245kv with fw 6.0. The 300kv detected fine in BLDC detection with sensors and 10A detection current, and both motors were spinning up fine on the bench, sensors were working great too. Then I got out my phone to take a video of the sound and when I gently pulled the trigger one of the motors just jittered and a mosfet blew up…

So I ripped those controllers out and put a Makerx DV6 in runnning fw5.2, and BLDC detection was just not working. However FOC detection works perfectly and I was able to ride the board with 300kv motors on 12S in sensored FOC mode. But FOC is shit imo and I want to use BLDC mode. So I tried messing around with some settings such as increasing detection current to 12A, and the erpm to 300, but the motor just spins up and then I get detection failed…

So my question is, anyone got ideas on why it might not be detecting the 300kv motors in BLDC detection, and is there a way to work out the values from FOC detection that I could put in for BLDC mode such as cycle integrator limit and BEMF coupling? And also the hall sensor table reading, as the table in FOC detection shows values from 0 to 255, whereas the BLDC sensor table is values from 1-6.

Any ideas would be much appreciated as I don’t want to give up on 15,000RPM square wave epicness

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FOC detection results of both motors

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Idk if BLDC mode development has happened in a long time. Might just be broken. Also FOC mode FTW

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Very bold statement, care to elaborate

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Lol I was wondering why the contrasting opinion as well

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Off topic

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Then I’ll be on topic.

You should just use foc.

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It doesn’t work properly. Cuts out under load, less torque, people can’t hear you coming. Not usable

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Off topic

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Take your pissing fight elsewhere. This is off-topic.

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Off topic

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I think he doesnt like FOC because the throttle response is poorer and you have lower top speed.

These are not inherent in FOC, just the VESC spin of FOC.

And yes Ive already pointed out ways to make the throttle response better, turn off the “decoupling” under the advanced tab.

ON topic discussion

BLDC shouldnt need detection, but vesc makes you do it anyway, try tweaking the startup parameters (different omega, higher I) and adjust different duty cycle detect, try lower since the kv is higher (vesc spins it up to a certain speed in open loop, if there is not enough duty cycle it doesnt detect?

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Try BLDC detection with default parameters

If unsuccessful, raise I to 10A, try again

If unsuccessful, raise D to 0.12 (12%), try again

If unsuccessful, raise ω to 250 erpm, try again

If unsuccessful, raise I to 15A, try again

If unsuccessful, raise D to 0.17 (17%), try again

That process hasn’t ever failed me with esk8 sized motors

But also just click the ? and read exactly what it says there; it’s actually really helpful.

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Thanks for the help @b264 @Gamer43
I will give these things a go and report back :call_me_hand:

I’ll also try FOC on fw5.3 out of curiosity to see if it performs better

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I’m also struggling to detect on bldc but detecting fine with FOC

12s
Og focbox
Fw5.2
TB6374 190kv

I’ve tried gradually increasing the values but the stuttering just gets worse and worse, like a fuckin jackhammer :rofl:

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Interesting. Try an older firmware with the same settings and see if it changes anything.

If it works, copy the detected Cycle Integrator Limit and the BEMF Coupling numbers to the new firmware.

It’s entirely possible that the BLDC mode has been neglected and not tested much in newer firmware versions.

I used BLDC exclusively, because I like it better, until HFI debuted and isn’t available in BLDC mode. Since then, I haven’t used BLDC mode a single time.

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Yeah its highly likely i’m gonna go HFI anyway so i stopped trying :rofl: hopefully HFI doesn’t blow up the focboxes.

/derail

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HFI actually works pretty decent on them. Possibly even better on the two-shunt hardwares than the three-shunt hardwares.

Make sure you tune it well.

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You were right on the money. I reduced detection ERPM and duty by 50% figuring 300kv is 50% more than 200kv and it detected perfectly.

Thanks heaps for that idea

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Also I tried FOC mode on fw5.3 and it was slightly better but still completely cuts power under more than say 60% throttle. I think its a DV6 specific issue as I never was able to get my 190kv 6374 motors to run on FOC without overcurrent cut outs