# Go Kart build

#### CjWright1986

Joined Feb 9, 2022
2
Hello all,
Amplifies of this has previously been covered, I did have a look but couldn't find anything to answer my queries.
Myself and a couple of friends have decided to venture into the realms of building A Go Kart.
We are hoping to use 4 motors, one on each wheel, independent suspension, and off road tyres.
All specifics are currently still being discussed to find the best option /combination for our application.
Our budget is small, but at the same time, we are not looking at making it as cheap as possible and compromising performance.

Questions
• Is there a speed controller capable of controlling 4 motors ?
• I've seen various threads saying that a diff isn't required - will any programming be required on a set up with 4 motors to allow cornering?
• Are there any examples of the already with a similar setup?

I'm sure there will be more questions through the course of the build.

#### Tonyr1084

Joined Sep 24, 2015
6,967
Welcome to AAC.

Most of motor speed controllers I know about are for hobby motors, the small stuff and use a 555 chip and some transistors to control the motor. What you might find useful is to look into tread mill motor speed controllers. It may also be helpful to define how much power the motors (each) are going to use, what voltage and what source of power you're thinking about. We can help from there. But I don't know that anyone here is eager to engineer a solution for you. Controlling four drive motors simultaneously isn't a simple task. At least not that I can imagine.

#### Tonyr1084

Joined Sep 24, 2015
6,967
Have you considered the amount of unsprung weight you're going to be dealing with having the motors directly on the wheels? One bigger motor and a transmission may work better. "ALL" wheel drive would be the way to approach it.

#### LowQCab

Joined Nov 6, 2012
2,157
How would You describe the amount of Acceleration, and ultimate top-Speed that You will be expecting ?
A Total-Weight vs Horsepower number would be a good alternative description.

Something with a long-travel Suspension might generally be expected to have over ~20-total-Horsepower
and be capable of climbing a ~45-degree Grade.

Have You ever seen how big a ~5-Horsepower Electric-Motor is, and how much it weighs ?,
and the serious Battery-Packs to handle all this.

There is a new crop of Electric-Dirt-Bikes coming on the scene, and they are no-joke,
I suggest that You check them out, and consider driving only the Rear-Wheels.

4-Wheel-Drive will do You no good without serious Power and "$Money$".
.
.
.

#### MisterBill2

Joined Jan 23, 2018
12,393
An interesting concept: 4 wheel drive.
With independent suspension and off-road tires and wheels and tyres, it will not be a "go-kart", at least by the definition that I am familiar with. It will be an "off road vehicle", a perfectly reasonable concept. Mostly such vehicles have two wheel drive and many are able to go fairly fast.
Motor controllers are indeed available, mostly for two wheel drive systems, but the good ones are not cheap.
Before spending money on the project you do need to decide what sort of performance you require, including acceleration and top speed. Then investigate the specifications of commercially available vehicles with similar performance, and see what horsepower they claim. That will be a bit more than an electric drive will need to have.
An example would be a vehicle with an 8 HP engine. You could use an 2 HP motor for each wheel and have better traction and better directional stability. But a higher performance HP brush type PM DC motor weighs at least 15 pounds, and so you will need some serious suspension and drive shaft arrangement. And the motor DC power will be at least 1500watts. So at max, the four motors will require 6000 watts of power, if your control system is very efficient.
So unless the goal is short trips, or the vehicle uses an extension cord, you will need a far amount of battery power.

Do you already have the drive motors for the project? If you do, let us know the ratings so that we can provide useful advice. So far I have only provided questions that need answers.

#### CjWright1986

Joined Feb 9, 2022
2
Obviously still a lot to think about.
As yet, nothing has been purchased, the idea is to make something completely unique at an affordable price (dreaming I know ) but I think that money will be spent if we can justify spending it...... (to the women in our lives)!!!

We had looked at hoverboards which have motors built into the wheels, but looking at how feasible this is, as we will have to make the original wheels into a more off road capable tyre.

Batteries we were going to couple together a fair few RC batteries?

All ideas at the moment. Not a great deal of knowledge on the matter, so still researching and brain storming.

#### MisterBill2

Joined Jan 23, 2018
12,393
You will need to learn about battery capacities. Watt hours as well as amp hours. That is why battery electric cars have not take over years ago.
And why, still, the price of the replacement battery for an electric car seems to always be about \$5000.

There is a whole lot to learn, which is why I did not campaign an electric dragster in 1967-68. And that one would have had pickups alongside the track, like a 400HP slot car, with a huge generator parked behind the pits area. Actually, 400HP per wheel, 4wd.