Noise and low power

General topics and discussions about the VESC and its development.
Posts: 7
Joined: 03 May 2016, 15:03
Location: Germany

Noise and low power

Postby schwibsi » 22 Sep 2016, 11:00


I'm using 4.18 firmware on a VESC driving a Bafanag BBS02 motor. Hallsensors are attached, too
Startup works fine mostly. But the motor is quite noisy and power output feels significantly lower than with the original 25A controller.
I have identical motors in two bikes right next to eachother, one powered by the original sine-wave controller, the other by the VESC.
With the original controller, the motor is whisper quiet, with the VESC it's quite noisy and even though the current limit is set much higher (40A instead of 25A) it feels much les powerful.
I have attached some screenshots of my configuration.

There is another thing that's strange. With the arrow keys on my laptop, I cannot control the motor within the BLCD tool. When I push the right arrow key it just makes a short crunchy sound, but it does not spin up slowly or quickly.
When used outside, I use the ADC in that receives a 0,8V-4.0V signal. That all seems fine.

I would really appreciate any guidance.
2016-09-22.png (113.88 KiB) Viewed 1010 times
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2016-09-22 (1).png (98.91 KiB) Viewed 1010 times

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Posts: 280
Joined: 15 Dec 2015, 08:38
Location: Sweden

Re: Noise and low power

Postby benjamin » 23 Sep 2016, 08:02

Your settings look quite strange to me. 120A current limit will cause several problems for a 25A motor, even if you only use a fraction of the throttle range. Some settings assume (e.g. inductance and resistance measurement) that a sensible current value is set. The minimum current should preferably be non-zero, e.g. at least -5.

The ADC cannot measure more that 3.3V, so setting it to 4V will not give you the full range for sure. Therefore you should drive the handle with 3.3v and not 5v, which usially works fine for most hall sensor throttles. When setting the range you should plot the voltage while doing that with control disabled and move it to max and min to figure out what the actual voltages are for the full range.

To use the keys in BLDC Tool you need to disable the throttle input in the ADC app, otherwise they will be overridden by the throttle input.

I haven't done too much testing on these kinds of motors yet, and on my ebike I currently have some hacks in the firmware to make things work perfectly. I will work more on these types of motors as soon as I have time.

Posts: 7
Joined: 03 May 2016, 15:03
Location: Germany

Re: Noise and low power

Postby schwibsi » 23 Sep 2016, 12:12

Thank you very much,
I am using an Arduino-based pre-controller to output the ADC signal for the VESC.
This also measures and limits the (battery) current to 30A.

I've lowered the settings to 80A phase current (I thought it should be about 3 times the maximum battery current) and 30A batter current.
"Batt min (regen)" is set to -5A... I had this set to zero as the motor has a freewheel and I thought it was not applicable.
What should I set the "absolute max" to?

Ah, I got that with the ADC tool now. I didn't know that.

Is there anything I can do to quiet down the motor with the VESC and maybe get more power?
Even at 15kph you cannot hear the motor with the original controller. The whistling of the motor driven by the VESC can even be heard going downhill at 50kph, if the motor is spinning.

I would really appreciate any help

Posts: 7
Joined: 06 Apr 2017, 12:59

Re: Noise and low power

Postby duststorm » 18 Apr 2017, 10:25

schwibsi wrote:I'm using 4.18 firmware on a VESC driving a Bafanag BBS02 motor.

Cool! :)
How did you manage to connect the motor to the VESC? I thought these motors had their controllers built in in a way that does not provide access to the controller or the individual motor phases.
How did you manage to connect it without breaking the motor?

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