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Dual VESC SIX eMTB, some offroad ridelogs

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Tue, 2017-09-19 13:33
#1
Squad
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Dual VESC SIX eMTB, some offroad ridelogs

Hi guys, some of You may know me from electric-skateboard.builders forum from my thread (http://www.electric-skateboard.builders/t/diy-trampa-long-35-e-mtb-dual-vesc-six-sensored-emax-gt5345/2474)

My board came through a long evolution to finally become what it is now, ultimate overlanding-offroading machine. Thanks Benjamin! 

My settings are 90A motorcurrent max, 60A battery current max, -40A battery regen, motors are set up in sensored FOC. My battery is 12S 10Ah.

I managed to throw few overcurrent faults while trying to bomb some pretty steep hill (wheels didn't have enough grip and started spinning in place few times). My heatsink on top of electronics enclosure was pretty good idea, mosfets reached 55 degrees celcius max temp during first ride and my heatsink became quite warm. 

Here is first log with uphill torture testing

https://metr.at/r/4jvCO

Here is second one

https://metr.at/r/ZXGey

 

Here is what my board had to deal with, "path" is an exaggeration, hardcore offroad.

 

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Sat, 2017-09-23 11:02
Pimousse
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Very nice board ! Congrats !

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Sun, 2017-09-24 23:06
(Reply to #2)
Squad
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Thanks Pimousse!

Today I had another pretty hardcore offroad adventure, I triggered over dozen of overcurrent faults

My VESCs settings are: 
Motor current max 90A
Motor current max brake -80A
Absolute maximum current 150A
Battery current max 80A
Battery current max regen -60A

Motors are running in sensored FOC (FW 3.29), any suggestions what to adjust to avoid overcurrent faults? @Benjamin, @Frank?

https://metr.at/r/nZEM8

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Mon, 2017-09-25 03:00
gohanok
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I have the same symptoms.

Motor current max 100A
Motor current max brake -100A
Absolute maximum current 150A
Battery current max 80A
Battery current max regen -80A

Motors sensored FOC (FW 3.28).

https://youtu.be/NvDqZfAjPz8

The road is climbing a bad hill road.

The motor stopped suddenly and I fell.

It is the last part of the video.

Error : FAULT_CODE_ABS_OVER_CURRENT

 

 

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Wed, 2017-09-27 23:16
Necromenz
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Hi,

i had the same Problem at very hard dirt Tracks but i was able to fix it. 

Frank told me Motormax = Battmax and thats it.

please post your faultreport. 

At the Video your Motor fault at over 100A and your battmax is 80A. I do not know how long the vesc tolerates this deviation. your motor uses more amper than you Give it from the battery free. 

I Hope it helps.

 

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Tue, 2017-10-17 21:00
benjamin
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In situations with bad traction the faults can come when wheels starts to spin and suddenly get grip again - then the current controller has to be very fast to adjust the modulation to prevent overcurrents. Setting the current controller time constant lower when calculating FOC parameters can help a bit, e.g. 500 µS. Lowering the current limits in general also helps. Another way to easier deal with faults is decreasing the fault stop time. 100 ms for example should work, but I haven't tried that. For experimentation, the high current sampling mode and firmware without limits + abs max current of 190A or so could be an option. I'm actually thinking of increasing the highest value for abs max current as the useful feedback from some users show that the VESC6 can handle a bit more current than I thought.
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Sat, 2017-10-28 16:25
(Reply to #6)
Squad
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Thanks for detailed reply Benjamin :) In my case faults occurred just like You said, wheels spun fast mid air then suddenly got grip. I'll try adjusting VESCs parameters just like You suggested, until my first post describing this issue I activated high current sampling mode, as well as increased motor max = battery max (90A) and absolute max to 180A, since then didn't observe this issue again (however I didn't ride in such rough terrain).

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