Noob question thread! 2020_Summer

Not sure about the tooth Count, but its definitely 5:1.
I am logging via Vesc App, it is using Phone GPS. It is Off by around 15-20km/h…

Im viewing the csv within the vesc Tool in PC.

If you know it’s 5:1 then just type in 1 tooth and 5 teeth.

Off a constant amount regardless of your speed, off 15km/h when you’re going 15km/h? Off 15km/h when you’re going 100km/h? We need more details.

OK I am an idiot. Set the ratio in one vesc, logged the other…

Any idea on the motor current issue?

Can you screenshot your motor current settings and upload the CSV log?

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100A battery max per motor sounds ridiculously high.

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It’s fine I guess. It is a mountainboard for offroading :grin:

But I just saw, the log says “Current Motors”, plural. I did not know that the log adds both values. Then its fine I guess.

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:man_shrugging: I run 80-100a on a single motor setup, seems fine to do so on a dual as well.

I’m almost positive it’s combining motor current as the field says current motors
image so you should be good.

yes, max value in Excel is 84 :slight_smile: Sometimes the VESC Tool is just too smart for me…

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I hope you have 8AWG wire or bigger exiting the battery.​

It’s 10AWG only. Had no problems yet and the current is only that high for really short burts.

Ohhh I misread this.

Yes, 200A total from the battery is… a lot.

So 100A motor each is OK
but you should set your battery amps on each ESC to (cell specification x p group / 2)

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If the current is that high for more than a few seconds, you will likely achieve atmospheric escape velocity.

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That is correct :joy:

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I mean its a 20Ah lipo rated for 12-24C. Lets say its 10C realistically then I still should be able to draw 200Amps for a short burst, right? If that ever will happen, which I doubt.

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You will only be able to draw 190A maximum, and only at exactly top speed. In reality, you’ve completely disabled the battery current limits. Top speed is precisely the moment when you DON’T need that kind of power.

Yes you are right, I could step down a little bit, but it is not really a usecase, is it.
I wont go top speed without dying :smiley: Thats just what happens when Jenso (no-wind) builds your board :joy:

Hello! I have a question about my motors they have this screaming noise at around 28 miles per hour and I have tried fixing it by securing the windings on the stator with adhesive. It still makes the screaming noise though so either I didn’t get the right spot or it’s something else. The bell or can is balanced and doesn’t vibrate whatsoever when at those rpms. There should be a video below that shows my issue. Should I just keep on riding and let dust eventually fill in the gaps of the windings of the stator that vibrate if any or should I try fixing it again with the adhesive?


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It’s fairly normal to have a change of pitch at full RPMs, but that does seem like a little more than usual and it sounds like a second pitch starts at half RPMs. The startup on the first and second video indicates that something is off too.

I’d just start from the basics and work from there. Make sure you are on the latest 5.2 firmware on both sides. Set defaults and run the FOC motor detection wizard, then run the input wizard. Swap phase wires rather than using the VESC invert motor feature if it’s not running in the correct direction. Try each motor separately to see if only one has an issue. Try FOC sensored, sensorless, or HFI and see if that solves the startup issue. To slightly change the pitch of the audible noise, you can adjust the switching frequency under Motors → FOC → Advanced. 20-35khz is probably a safe range to experiment in, but it depends on the ESC model.

If you are concerned about loose windings, use a multimeter to make sure the phase wires aren’t shorting to the can/shaft or search for “battle hardening” on the forums and see if that’s something you want to take on. Hold the wheel so it won’t move and try to move the can by hand with some decent force. See if there is play in the outer shaft and tighten the grub screw with Loctite if that’s the case. Depending on how those magnets are secured, a loose, crooked or unevenly spaced magnet can cause odd noise problems at various RPMs. Make sure the bearings have no play in any direction and spin without being “crunchy”.