@hazza i will not use vesc traction control, it is no good for 4wd with this much power. Reason is that you select 1 wheel as “master” and the rest follows. Front will have less traction than rear which blows it. Inside the motors there will be additional hall sensors connected to separate TC board, all wheels independent. It will allow for much more control than build-in solution and accelerating with rear while braking with front for sharp turns with powerslide. Separate controls for braking and accelerating. @b264 Briefly considered using this chip but it has only 1 amp mosfet driving current and is slow as armored turtle. If you read the datasheet and understand it it becomes clear. Chips i chose offer 6 amps driving current at 120 volts max supply, transients up to 150 volts and they can be connected in pararel to give even more current, which i did. This will allow me to keep switching times very low, in the 10-15 ns range. Dead time will be something like 20 ns. Original VESC 4.12 has a dead time setting of 180-220 ns. If i used DRV8353 it would be like 300ns with the amount of mosfets used and their combined gate capacities. Anything less blows the fets to heaven. After my analysis i deduced that almost half of the heat in old vesc is generated not by conduction but by switching losses. Did not want that.
What chips did you choose with 6A driving current?
But as said already how will you keep traction with that much power? You’ll need super soft tires and lots of contact. I can spinout my tires on even my two normal hub motors using typical settings and 78duro
Check Maxim dual high side drivers on mouser, you will find them. For the rest of the people it is a company secret.
Beyond the actual traction limit of 4 wheels spinning, all the extra power beyond that should just be applied to making loud roaring sounds to make it seem even more powerful.
It seems better to make it a street luge and then u could at least hold on.
There’s surely some math revealing how much tire contact and what duro for what wattage at what weight to stay stuck to the road and not just burnout. I think be worth doing.
All Trampa electric mountain boards have foot straps, just like snowboarding. That may seem nuts, but after riding my Evolve GT and my Trampa E-Mountainboard(strapped), I much prefer the foot straps. There is a lot you can do with straps that you can’t do without them (though falling truly sucks ass!)!
Holy shit
This is just insane! And I can’t wait to see it when it’s done. I will def. be following this build.
Then get some snowboard bindings and ty it too. Tried both and stayed with snowboards. Bindings alone give +20 Kph to speed wobble limit, control is much better and sharper. It allows much tighter turns. I have several friends who do mountainboarding and all of them had injuries of either knee or ankle bencause during crash 1 foot got out of the strap and the other did not, twisting the leg. With bindings you go visit the ditch together. Done that enough times. Also the difference is that with bindings you 95% crash on your butt, which is actually better. The only downside is that you cannot push yourself with your leg, which is of no importance on the electric.
Not at the speed you’re aiming for, the two proper get offs I’ve had were with Trampa bindings with no heel straps, I came out of the bindings, flung really, but that was only 57kph and on sand. If you get into a wobbler there is no adjusting position
Since you seem to keep ignoring my and hummies question, I’m guessing you haven’t solve the traction issue. I can tell you with 10k watts 4wd with 78a urathene, I break traction on every full throttle acceleration. To put 8k to each wheel would mean you need almost 4 times as much traction as I have with my 78a duro wise contact patch urathene wheels.
I’m not trying to hate, but considering your building your own hub motors and I’ve yet to see any other eboard you’ve built, I’m trying to give you the inside experienced knowledge from someone whose been trying to push bouderies with his builds. I would be doubful if you can find a pneumatic that can take 4K watts per motor and not lose traction, none the less 8k. It just seems like you’ve picked some crazy specs arbitrarally without any experience of what something even a 4th of that is capable of.
As someone whose skated street for 11 years and eboards for almost 4 years, I can tell you that it is incredibally hard to commit to the acceleration at 10k watts. I’m sure the straps will help.
I guess my point is do the math on traction and figure out what will work. The last thing I want to see is you build these motors and realize you lose traction and need to redo the motors to fit a wheel with a bigger contact patch.
He just has to put some lead blocks in the front and the back. Thankfully friction is proportional to normal force. But sure he needs the wheels that can handle that traction.
I do not ignore, i have simply done my math. Recalculate using torque instead of watts. Your build has more torque per watt than mine at the expense of much lower top speed. I will get 240Nm on wheels at 1400 motor amps combined for 4 wheels. Battery being 20S plays a big role in those calculations, increasing top speed at given amps. At tire radius 125mm it means 195 kgs of driving force. Gokart supersofts have a friction coefficient of 1,6 which means that if the board + rider weighs more than 121 kgs tires wont spin. Urethane has half of this friction coefficient. I top at 90 kgs, board will be hair short of 30 kgs. Math fits. If you do not believe use the calc yourself https://calc.3dservisas.eu/ . Target motor kv 50 motor in wheel so 1:1 gearing ratio motor config 36s42p. Current per motor 350 amps.
I’m lost in your lipo math.
I run a 2x 6s5p packs to make a 12s pack from these cells: https://hobbyking.com/en_us/zippy-compact-5000mah-6s-25c-lipo-pack-xt90.html
With 5 in parallel, that’s a 125c rating. And with 44.4 nominal as in my case, this is over 5000a. My 12s battery is only 6.5 kg. Now you wouldn’t be able to hit 20s with this battery (18 or 24 yes), you can see this battery would be lighter than the li-ion and also far more powerful. It will also sag a lot less.
Putting the cells in pararel does not increase C rating. Only the capacity. If i put 4 cells of 5000mah 25C in pararel i get 20000mah still 25C, meaning 500 amps. Good. Then to get to 20S i need to put 4 packs of 5S in series, which increases voltage but not the current. 4pack series x 4 packs pararel = 16 packs.
ok, sorry, missed where you mentioned your using go kart tires.
Still, not sure where you are, but I think you should try a really powerful 4wd before you get too deep. with 10k watts on 84mm urathene with 85kv, I hit 0-20mph in just over 2 seconds. Your going to theoretically do it in a 3rd of that time.
I love how this build ignores physics 
Keep it up 
New Winner if this works out
84mm 85kv is equal to 250mm 28kv (imagine you applied gearing). Mine is 2x greater at 50kv - 2x less torque per amp, 2x top speed per volt.
You get 20 MPH in 2 secs, i get 60 mph in 3 secs. Acceleration is 2x greater, so is the friction factor of the tires.