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AWD Eskate-Kart | 100kv Maytech hubs | 4.12 FSESC's | Left and Right throttles

This is my first build. I am using it to prototype an idea I have for a “micro-kart”. I am a Product Design student in my senior year and this is part of my thesis into “the driving experience” for driving enthusiasts.

Specs:

  • 4x 100kv Maytech 90mm hub motors
  • 4x 4.12 Flipsky FSECS’s
  • 10S7P 30Q battery
  • Teensy 3.5 development board
  • 9 ply 1/16th” Maple Deck with epoxy
  • fiberglass enclosure
  • modified Razor kart steering components
  • laser cut 3/16" metal components

What I started with

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I originally ordered a 10s2p battery and then learned about max amp output so I built it up as a dual motor board just to press forward with a moving object. I had each VESC motor tuned to the ~30A the FOC wizard came up with, but the battery max output to 15A (for a total of 30A max battery output)

This setup went around 27mph but was lacking in the acceleration dept.
image

I then ordered a 10s5p battery, ordered 8awg and 10awg wire as well as XT-90 connectors and programmed the VESC for battery max amps to 18.75A (for 75A max total with all 4). I did this with the 10s2p battery connected because I wasn’t going to run it with any load for longer for 10 seconds, just to feel what the board felt like that I was actually trying to build. The bigger battery is in the mail and I am soldering the new wires and connectors this weekend.

I am super happy with the acceleration of this thing now and look forward to some more research and testing. It is scary quick for a skateboard and it should make for a fun toy!

Here is one of my first sketches of a bent plywood go-kart from this drivetrain.

This is a work in progress and I appreciate any comments and questions.

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can anyone suggest how to rotate pictures? they are all showing up rotated 90* counter clockwise…

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I love the drawing! Looks fun already.

Might need a metal subframe, and I’m interested in your plans for steering geometry.

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This is a great build so far. If everthing works, the fun begins in different ways. Personally im not a fan of the kart idea, bc its more like a car than a skateboard and I (we) need powerfull, reliable, waterproof electric skateboards even if your marker sketch of the vehicle is really awesome.
But anyways, hold on to your ideas and please finish the board hahaha

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I am researching steering geometry currently… it will have to get figured out before the vacuum molds get made for the “deck”. There are some premade options such as This from Razor for one of their karts … any will need some modification, but it’s a start.

I’ll probably model some stuff and 3D print mock up pieces.

I am hoping to not need a metal subframe but we will see. I think the main deck will be 2 plys thicker than a standard stiff deck.

Right now I am getting the “drivetrain” sorted and between turkey dinners I am soldering 8awg and 10awg splitters and loop key.

10s5p is coming Monday! Then I have to try and fit 10lbs of tech on 5lbs of deck hahaha

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image

[battery]
8awg loop key (with anti spark)
XT90 splitter
2x 8awg pigtails
2x XT90 splitter
4x 10awg pigtails with XT60 connectors
[VESC]

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While this may not make sense to you just hear me out and take it for that it is… (I am trying to cross the realm of esk8 and create a micro kart with torque vectoring.)

If I have 1 battery, 4 motors and 2 remotes (with their respective receivers) could I have 2 motors controlled by one remote and 2 by another?

I am pretty sure the answer to this question is yes.

Now, if one remote was braking (as in regen) and the other was pulling power (accelerating) from the battery what would happen? With powering going back to the battery and getting pulled from the battery?

if one remote was braking (as in regen) and the other was pulling power (accelerating) from the battery what would happen? With powering going back to the battery and getting pulled from the battery?

Anyone have any thoughts?

Also, with 10s5p and 30Q cells what is a safe regen amp to send back to the battery?

New battery just showed up today and will be strapped up and tried out tomorrow… gonna be a lot of stuff on the bottom of this board until I take steps towards the micro cart and have more space.

From everything I’ve seen people talk about from testing, battery Regen really doesn’t account for much of anything.
Even going down a long long hill breaking the entire time barely gets any substantial power back into the battery.

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I am concerned for the BMS if voltage is going in and coming out.

I could just make -0 Amps of regen go back to the battery and keep it at -30 at the motors I guess to be safe.

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and me stupid always begging for a steep long downhill when my batteries are low, hahahaha jk…
imo the regen does its job but its not like you can get endless ride but if i can regain 10% or just 5% its better than nothing. If there is really NO regen im a just fantasizing. :grinning::hugs:

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Followwiiiinng !! :stuck_out_tongue: :+1: Love the drawing !
It could be a cool funny idea !!

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Build will be back in progress after school starts again after the new year.

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Back at school working on finishing up the concept before building goes further. Also working on trying to receive a grant to cover some of the costs… I am at something over $1200 already.

I had an issue with the hall sensors in one of my motors and @Eileen was super helpful with trying to troubleshoot it and eventually I trouble shot it down to a bad halls sensor. I bought 10 on eBay, removed the one that was showing different volt and resistance readings and it is all good to go again. Here are a couple pics of the removal. (I had no idea they slid into grooves in the stator until I was trying to remove it.) Also this is mid removal and I had already cut the leads… it wasn’t this obvious that it was the issue hahahha

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Had the board out for a few miles this weekend with the warm weather and the sensor issue is back. I am hoping it is just my soldering but we will find out when I get to rip it apart tomorrow.

The build will be starting back up very soon with sketches, modeling, and maybe some 3D printing of components to later be made out of metal.

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Halls sensor I replaced, tested bad again. Replaced it again and it is back to running smooth as butter… I hope this isn’t a problem that happens every few miles.

I will be starting to flesh out the building of the kart frame/ deck this week. Pics to follow.

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Idk why this Gif is upside down… but whatever
image

Got the joystick throttles and throttle displays coded… now to wire the left and right joysticks to the appropriate speed controllers for manual torque vectoring.

Going to start to do some Solidworks modeling of the Kart chassis to later CNC Foam and make molds to vacuum bag the plywood chassis around.

Things are continuing!

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Working on getting angles and scale right so a wider range of people can fit on it than just myself.

This is just to get an idea of the final angles and work out the kinks before I model it in Solid works before I order the veneer and cnc the molds for vacuum forming.

Had a break through on the steering that should make fabrication about 33% easier so that’s rad.

:+1:t3::+1:t3::+1:t3:


Adding this link for future reference.

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This is rad! What kind of led strips are you using btw?

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They are on a single I2C with different addresses assigned to left and right LED’s

These are the joysticks.

Adafruit is rad for all the stuff they have available and support with DIY’s and sample code.

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