SK3 245 + 6S + VESC problem

Hi Builders,

my e-longboard died and I decided to build one by myself. So, went with the following spec:

  • SK3 245KV 6364 motor + additional HAL sensors
  • 6S battery (24 Sony VTC6 3000 mAh 30A)
  • VESC 4.12 - seller said he upgraded components thus it’s able to work under 240 A

rest of the set is not worth to mention. However, I faced a problem with the engine (or VESC). When it runs without a load, looks that everything is fine, while when I’m standing on the board and try to start, the engine is breaking in a weird way. Here you can see an example:

Also, I’ve noticed the board’s acceleration is far away from the previous spec. Do you have any ideas what is wrong?

Best regards, Arek

What’s your motor max and battery max?

I have this motor [](http://Turnigy Areodrive SK3) so specs is as follows:

  • motor max 70 A
  • max voltage 37 V


  • 1 cell has max discharging rate @ 30 A, so as far as understand 4 cells in a row have 120 A

To setup my vesc, I tried with values equal or higher than above:

  • current motor max is 100 A
  • current battery max is 110 A

I’d suggest turning those down. Start with 60a motor max and 40a battery max.

That’s some bad cogging that’s going on.

Let’s see some pictures of the VESC too

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Ok, thanks, will give you feedback asap

if you give the motor too much current it will demagnetize the motor thus needing more current to accelerate…a vicious cycle Btw starting from standstill without sensors is kinda unhealthy for the motor


@Colson003 @Benjamin899

So I changed settings according to your suggestions but before I go for a test ride, I would like to ask you to take a look at my VESC settings.

28 09 58 33 01 38

looks good to me

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You could decrease the motor min to -50


i love that you said decrease^^

@Colson003 @Benjamin899 Guys, thank you for help so far. I did a test ride and it’s better now. However, after 2 km I stopped to check if engine temp isn’t too high and after this break, I had a problem to start. Similar problem like in the movie I posted yesterday. Also, slow climbing on the gentle hill was a huge problem for the skateboard (batteries fully charged). However, on a flat route, I made 33 km/h so I’m more than satisfied. The only change I made before I ride was to increase startup boost to 0,04, could it be a problem? Do you have any ideas on how to diagnose a problem? Probably additional Bluetooth module and iPhone app is the only solution to getting know what is going on?

did you run a motor detection? if it coggs you need to increase the duty a bit, dunno how much, normally there should be a tooltip in what increment you should increase it. 33km/h is quite fast, remember you have a 6s battery. And top Speed is also determined by gear ratio. Also climbing hills with a single drive is also realy straining for a 245kv on 6s. How much do you weigh?

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yes, I did a motor detection. Currently realized that my custom HALL sensors are causing problems, so I’ve thrown them out. Will do a test ride and will let you know. I weigh 75 kg, on the previous motor (do not know spec) and controller I was able to make 25% uphill every day, with pain but it was possible, currently, 10% is impossible, so somewhere I made mistake setting up the skateboard :slight_smile:

i am guessing the old motor had lower kv so it was easier at 6s to climb. I would like to know your wheelsize and gear ratio.

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What brand esc is it?

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@Benjamin899 My gear ratio is following:

  • 82mm wheels
  • motor pulley 15 teeth
  • wheel pulley 53 teeth if I calculated correctly :slight_smile:

@Colson003 The first electric skateboard was 1st gen Majestic Boards product, a small Polish company. It had a single motor, 6s battery, it wasn’t a beast but it worked fine. After two years the battery has degraded and shortly after a battery replacement, the motor died. Current spec is in the first post.

Did a ride without sensors, and it looks that if I push throttle rapidly, the engine blocks itself - made a nice flight before noticed this issue :slight_smile: So when I speed up gently, it goes even uphill, but once I move throttle to max, skateboard slows down or motor blocks itself.

i doubt that your wheel pulley has 53 teeth, not on 82mm wheels or wait, what pitch do you have

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Sorry Benjamin, don’t understand your question…

What is your Tooth pitch on the pulley, i doubt it is 5M.

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Sorry, I had to google what is tooth pitch :slight_smile: I don’t have a precise tool to measure it, but it looks that it’s 5 mm. And counted twice, 53 teeths :slight_smile: IMG_0500