instructables
Mini Electric GoKart
by MatthewW147
There are quite a few GoKart Instructables here and Threaded Bar - M8 and M10 (Recommend Stainless
in order to build mine I had to browse them all, The Steel although pain to cut)
forums were also incredibly useful. What I will try to
do here, is give a brief outline on how I built GoKart in Brackets - came from same supplier as the extrusion
the picture, provide the links from where I got the 2.50 SGD per L includes the hex bolts and 'nuts'
information and how I interpreted it, the equipment I (expensive but reusable and adjustable
bought "and" used and some key information in
getting it to actually move. Nuts and Bolts - M6 up to M12 used Locktite should
have gone with Nylocs
I used aluminium extrusion throughout, it's more
expensive but reusable and you don't need any water Bearings -SKF 12SGD per cassette. (needed to turn
jets or CNC's to get it usable. down the inner hub of each wheel for a snug fit but
you can emery them down... not the bearings, the
All in all the kart took several months, mainly because wheels)
of work taking up mental and physical time, I should
also explain now that I have a full workshop however Wheels - WBR250x60 12SGD each -
I tried to keep the build as simple as possible and use http://bit.ly/2b8a8Gl
as many generic parts as possible.
Seat - Old school chair from bin
You may see prices in USD, SGD and GBP, I'm
based Singapore so most of the time I had to look to Steering Wheel - OMP 11 inch Steering wheel
specialist items else where. Just to note though.. https://mikimarketing.com/ (Prices online are wild!!
USD and SGD are pretty similar, 100 USD + 1/3 will but if you can visit the guy, and tell him your budget,
give you the SGD, double the GBP will give you the ex display old stock goes very cheap)
SGD, I could have got much cheaper equipment from
Alibaba.com but what with so many potential issues, I Brakes - got cable disc brakes from
decided to reduce the chance of error and stick with chainreaction.co.uk
what others recommended.
Throttle - THR-91Standard Steel Foot Pedal Throttle
Parts (mm unless stated) (THR-91) $29.95USD - http://bit.ly/2aUEDg0
Extruded Aluminium - 30*30*6000 - From 36SGD @ Battery - 2x 12v Lead Acid.. absolute rubbish but
5 metres cheap and quick to get going
Aluminium Round Bar - 12mm Dia Fuse - FUS-355ATO Fuse Holder with Cap (FUS-
355) and 30 Amp ATO Blade Fuse (FUS-ATO30)
Mini Electric GoKart: Page 1
$2.50USD
Speed Controllers - 2 x KBS48101X,40A,24-48V,
Mini Brushless DC Controller () = $238.00USD (for
the pair) High Speed Motor Option Unselected -
http://bit.ly/2azS0j8
Motors -2x #SK3-6374-192/18129 Turnigy Aerodrive
SK3 - 6374-192kv Brushless Outrunner Motor =
$151.24 (for the pair) - http://bit.ly/2b3iD4L
Halls - HONEYWELL SS411A Hall Effect Sensor,
Bipolar, 20 mA, TO-92, 3 Pins, 3.8 V, 30 V 5SGD
each - http://bit.ly/2azRe5A
Terminals -terminal blocks for 240V rating
Jacks - DJ7091Y-2.3-11 - http://bit.ly/2b8bUHs
DJ7061Y-2.3-11 - http://bit.ly/2aM8JCT DJ7091Y-2.3-
11 http://bit.ly/2aM8JCT (Highly recommend you pick
the corresponding male or female jacks depending on
the connectors that come with your controller)
Driven Sprocket- 2* SPR-254747 Tooth Rear
Sprocket For #25 Chain (SPR-2547) $15.95 USD
each
Driver Sprocket -2* SPR-251212 Tooth 8mm Bore
Sprocket For #25 Chain (SPR-2512) $9.95USD each
Chain - Style: 10ft min Riveted - Single StrandType:
Roller chainPitch: 1/4"Specification: ASME/ANSI
B29.1 - http://www.hikari.com.sg $30SGD
Relay - 12v - 240V
Diode - this comes with the Kelly controller
Pre Charged Resistor - this comes with the Kelly
controller
Switch - Sparco would have been my number one
choice but crazy price
Mini Electric GoKart: Page 2
Step 1: The Chassis
I owe all of this to extruded Aluminium, in fact Kart when driving it..
extruded Aluminium makes up nearly every part of
the chassis including the steering. The frame was held together with the corresponding
angles and brackets as pictured. These aren't the
In order to make the most efficient use of the most cost effective, Chibikart
extrusion began the design process by sitting on the (https://www.instructables.com/id/Chibikart-Rapid-
floor and using masking tape, mapped out an Prototyping-a-Subminiature-Electr/) suggests, as do
approximate chassis about my person. I had an old many of the other Mini-eGoKart designers that you
school chair, the legs had been bent, these were use fabricated brackets, these are stronger and
removed and the plastic seat decided where the cheaper, however the more expensive brackets,
reinforcements would go. I used 30*30 and about 6 usually available from the extrucion supplier can be
metres of it, this was useful as it came in 6m lengths. reused and rearranged so as to provide you with
more flexibility in your early designs. There's nothing
In retrospect I feel that the chassis may have been stopping you from sorting yourself out with your own
too small, the space for the electrics was pretty tight fabricated parts later on, it'd probable be a little safer
and you'll see the this led some of the terminal blocks as they'd be more reliable and hold stronger due to
to be mounted on the seat itself. Also by having a the increased moment within the holding structure...
such a short chassis, the steering is hair raising to However for ease, I went with the prefab brackets.
say the least. I also look like Donkey Kong in Mario
Mini Electric GoKart: Page 3
1
1. 90 deg Aluminium angle. This
one has an 8mm hole drilled
into it.
2 1
1. 6mm bolt with external locking nut
2. 6mm hex bolt and profile 'nut'
Download (https://cdn.instructables.com/ORIG/FO7/X3I1/IRLQG5GG/FO7X3I1IRLQG5GG.pdf)
http://www.instructables.com/ORIG/FO7/X3I1/IRLQG5GG/FO7X3I1IRLQG5GG.pdf
…
(https://cdn.instructables.com/ORIG/FO7/X3I1/IRLQG5GG/FO7X3I1IRLQG5GG.pdf)
Mini Electric GoKart: Page 4
Step 2: Rolling Chassis
Wheels - http://bit.ly/2aGr8kd Bearings - SKF 10mm internal diameter
I think I went a little over kill on the wheels, however These weren't cost effective but I had saved on the
these were unwanted items due to the large internal castors so it was necessary. The internal dia of the
dia. The good thing about these pneumatic castors bearing was 10mm this was due to choosing 10mm
was that they were held together by 4 removable threaded bar as the axles on both front and rear sets
bolts, the holes enables me to map out the holes of wheels. The front steering assembly is explained
required to secure the drive sprocket. (Will go into this later, the rear wheels are very simply held in place
later) Due to the larger axle holes I had to bore them using the 90 deg angled brackets
out a micron and place two sealed bearings into the
central axle hole.
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Step 3: Steering and Brakes
Steering rack - The steering was assembled using the currently working on a similar design to the bracket
same extrusion 30*30 and the accompanying that holds the steering wheel in place.)
brackets. The aluminium is very soft so it can be cut
easily however be warned the wear upon the parts On trial, the steering is hairy, spins on a dime and the
that move against the threads could quick easy G force hurts. This kart needs to be longer and the
jepodise the kart's integrity.. However as long as you steering needs to be more merciful.
know this, you'll hopefully be looking out for it. I used
mild steel threaded bar, and although this has worked Braking systems - what went wrong
out I'm mindful that it's beginning to bend under the
dynamic loads when in use.. I'm looking into machine Originally I had purchased 2 Hydraulic Disc Brakes
bolts and stainless steel threaded bar. (The later is a from Chain reaction cycles these were going cheap at
pain to cut without machines though.. so be warned) 19GBP each, no longer at this price (
http://bit.ly/2aVyqyt) I really don't recommend these.
Steering column - The steering column itself is an They have been a pain to calibrate since delivery,
aluminium rod, 12mm dia, I turned it down towards constantly pinching the discs and really slowing the
the end to 11.5mm (lathe) this was to prevent it from wheels. I've since bought a bleeding kit, spent hours
slipping through the angled bracket, this can be seen calibrating and they still refuse to let go once the
fixed to the two uprights towards the fron of the seat. brakes have been activated. A few days ago I gave
There's no reason why you couldn't use a nylon cable up on them altogether and have moved onto
tie or aluminium collar cut from a lightly larger tube mechanised, cable activated disc brakes from
and pressed into the rod via a hammer and centre amazon. I've seen others use the cable brakes and
punch. now I understand why. Spring loaded calipers should
release the pads instantly and you wont need the
The end of the rod has been flattened on the tangent extra equipment to trim them. The original brakes
and a D shaped hole was made in perforate actually ripped one of the discs out of the wheels, you
Aluminium sheet so as to form the moment arm for really get some torque with the motors listed used in
the steering rods. (This actually failed during a test this build.
run, the metal was too soft for the turning force and
the steering rod ripped through the plate. I am
Mini Electric GoKart: Page 7
1
1. upside down brake levers double act as a foot pedal. Held on with nut
and bolt and several large washers.
Mini Electric GoKart: Page 8
2 5
4 3
1
2
3
1 6
1. Exploded isometric of steering arm. 1. Steering arm connected
2. 10mm threaded bar 2. this 10 mm threaded bar goes through the front bar
3. bracket drilled with 10mm dia hole 3. Front bar has been rounded
4. recess cut and filed to allow for nut to hold threaded 10mm. This will be
the axel
5. you need to assemble this first or you wont be able to fit the 6mm hex
above and below on the opposite bracket
6. you'll need nylon locking nuts pretty much all over however these have
been an issue to source. I used LockTite
Mini Electric GoKart: Page 9
1
1. scrap extrusion to support an aluminium round bar, 12mm dia
Step 4: Drive Sprocket and Rear Wheel and Motor
Because of the extrusion and the fact that you can adjust and tune the brackets, attaching the drives to the chassis
was easy. in order to be able to tune the brake discs and driven sprockets everything is connected via threaded
bar and nuts and locktite. this means you can use washers or shim to adjust the ride.
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Step 5: Electrics
This was by far the most confusing at first glance, wires and fix the components where they were
however everything revolves around the controllers. I mapped. I used a lot of cable ties.
opted for the Kelly Controllers which had a good user
base and reputation, and so far I've not had an issue The Kelly controllers can take a huge amount of
with them. The first part was to download the data voltage but need at least 24V to work.. Having exactly
sheet or spec outline for the particular model. 24V in the two Lead Acids meant that they needed to
be fully and utterly charged before I would get any
Follow the schematic as if you were building the Lego response. Those blinking red lights! I tried to connect
Deathstar or whatever. I used a laser cutter to not the system to a 36V LiPo from an old e.Bike but
only cut out the wooden board for the electronics to although the motors spun, under load they did nothing
sit on, but I also use it to raster (etch) the circuit at all.
schematic, that way I simply needed to follow the
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Step 6: Calibrating the Hall Sensors
This was a pain, I had originally created an adapter in allowing it to be twisted and pulled for fine turning.
fusion 360 and 3d printed it out, but it was the for a The STL's are attached. they are for the Turnigy
much larger outrunner dia, weeks of watching the featured in this kart though.
motor stutter and finally gave in and found some
online. Just before they arrived I was messing about I never did use the ones I bought, funnily enough they
with one of those clamps you get in science, holding had also been 3d printed! Some clever people know
the hall sensors at different distances from the motor how to make money.
and it suddenly kicked into high speed. And what
speed! Back on fusion I redesigned the bracket,
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Download (https://cdn.instructables.com/ORIG/F4F/LBBY/J8QGEUB6/F4FLBBYJ8QGEUB6.stl)
http://www.instructables.com/ORIG/F4F/LBBY/J8QGEUB6/F4FLBBYJ8QGEUB6.stl
…
(https://cdn.instructables.com/ORIG/F4F/LBBY/J8QGEUB6/F4FLBBYJ8QGEUB6.stl)
Download (https://cdn.instructables.com/ORIG/F2K/AY17/J8QGEUB8/F2KAY17J8QGEUB8.stl)
http://www.instructables.com/ORIG/F2K/AY17/J8QGEUB8/F2KAY17J8QGEUB8.stl
…
(https://cdn.instructables.com/ORIG/F2K/AY17/J8QGEUB8/F2KAY17J8QGEUB8.stl)
Mini Electric GoKart: Page 21
Step 7: Finishing Up
Once the turnigy motor were kicking in, everything others are located at SUTD in Singapore.. I'm not
else was very simple. Although I used locktite (Blue sure they still do the Chibukart project with MIT , I
and Red) I should have gone with Nylocs or even think they've moved onto the Shell Eco Challenge or
castle and pins. The lack of suspension knocks the something..
chassis around something crazy and within 5mins
you're sitting on the floor with just a steering wheel in All in all this was an expensive project and it really
your hands. takes it out of you. But once you've done it,
everything else is just a piece of .... pie? Originally I
The drive sprockets on the Turnigy spindles will come had thought of turning this into a school activity but
off, they're held with tiny lugs that can't resist any it's far too fiddly. Instead we now make 3 wheel
torque or shear. I had to use the holes (two) on each gokarts from extrusion and front wheel drive
sprocket and mark two dots on the Turnigy drive eScooters.. Will post that up later.
shaft, then use a Dremel and a conical abrasive head
to work dents into the shaft, this will give the lugs Good Luck if you're trying this, if you need any of the
(once you've sharpened them a bit, something to grip original Fusion 360 Files or more information let me
into. know, otherwise I'm closing this one.
The first photo and the 2 vids are of my gokart, the
https://youtu.be/vcoCSiCIc0s
https://youtu.be/4ut4Ma08TGc
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