Motor stuttering during braking?

I just put my build together and it runs fine except during braking - when braking fully, the motor will slow down, then at some point it’ll disengage and start to stutter, like a quick blip of braking every half second, like it’s being limited. This is only during full braking. I set the maximum brake current to 40 A, but it doesn’t exceed 8 A before cutting out during full brake. When I brake around 80% (estimated), I have no issue and came come to a full stop, and the braking force I feel is greater than the force I feel when the motor starts to stutter. Motor is FreeRCHobby 63100 140 kv with dual FSESC 4.20 running in single mode. Could it be an issue with any motor settings like duty cycle?
The ESC is on FW ver 3.103 and I’m using the Ackmaniac VESC tool. Remote is a VX2. If I try to check the throttle/braking curves in the UART window, it’s blank:

What is the power transmission method? This sound more like you’re experiencing belt slip than a motor problem.

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Chain drive, there is no slipping. The braking cuts out if I brake at the maximum after a few seconds.

What are you’re current settings? They roughly translate to motor negative current being high speed brakes and battery negative current/regen being high speed brakes.

Do you have the ability to data log this problem with a BLE module on the esc? Graphs would help to understand what may be causing this.

Also this is a rather large motor for such esc, it can only deliver about half the power the motor should be able to take

The 63100 was the best motor I could get for the price, even if it’s overbuilt. I don’t draw more than 20 A anyway.

Would it have anything to do with the duty cycle?

up the absolute maximum current to the biggest number vesctool let u, iirc it should be 150 or something


Unlikely. But as @frame pointed out the abs max current is way to low. That is a hard cut value. You essentially never want to hit it.

Also you wattage limits are low, but that may be because the current values are so low.

Did you run the detection wizard? What did the motors detect at?


I would run the detection wizard again, and like the others said, up the absolute current number. Did you check the correct size motor? How many poles does the motor have?

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Raise Absolute Maximum Current to the highest number it will allow you to save. Likely 150A.

Lower Fault Stop Time to 85ms.

Not a problem neccessarily, but 20A is really low for motor current max. I don’t know what motor you have but on the FSESC 4.20 maybe try 50A or 60A.

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It looks like the motor has 14 poles, which is 7 pole pairs? The VX2 has a setting for pole pairs and I set it to 7

I upped max current to 80A and set the fault stop time to 85 ms, still same result. Currently running it sensorless because the sensor wire adapter is still in the mail… could that have anything to do with it?

What do you mean detect at?

What is Absolute Maximum Current set to?

He means what number was produced during motor detection that was labeled “A”?

It was unlikely to be exactly 20.00

Did you read the settings first, change them, then write the changes? Or are you just changing them?

That change alone should be very noticeable, aside from anything else.

Did you setup up the Motor Wizard in the Welcome page? That’s normally the first things you should do.
Warning: this will invalidate all the remote AKA “APP” settings. So Motor Wizard>Input Wizard.

After the end of Motor Wizard (just after the motors spin up and do their detection) you’ll be prompted with a screen
Something looking like this but they won’t be the same values.
So the Motor Current is what the vesc tool calculated you motors to be capable of. In reality a lot of users here including my self double the value (as long as it doesn’t exceed what your motor is actual rates for on its spec sheet).

As for the rest, all you want is that the values between motor 1 and motor 2 to be similar, and make sure sensors are recognized if you have any.

Edit/ I may be wrong about what exactly Motor Wizard erases, but it definitely puts a lot of values back to default… Which you then have to go back and add

The remote does not matter, it needs to be set in the controller. Your problem sounds like an incorrect set up motor, thats why I was suggesting to run the motor setup wizard again.

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