My Cheap Homemade Electric Go-Kart Works Way Better Than I Imagined
Who would’ve thought less than half a horsepower could be so fun?
When we last left off, my cheap go-kart didn’t really work. I’d sourced everything and assembled it all, but when it came time for the moment of truth—the first test drive—nothing happened besides a bunch of noise. This was admittedly a little funny, but mostly disappointing, and I immediately set about finding a solution. Though learning new things along the way is a reward itself, the project would be an abject failure if it could barely move under its own power.
For those who might have missed part one of this saga, you can find it linked here. The gist is I’ve set off on designing and building a cheap electric go-kart for adults that anyone can construct for under $1,000. Why? Go-karts are great, and cheap things often suck. I want to prove that you can have it all: a go-kart that's well-made, easy to assemble, legitimately fun to drive, and light enough on your wallet.
The build process went smoothly—and stayed well under my budget cap—but because I’d opted for a cheap mystery motor controller to save money, the kart failed to run.
The solution was pretty simple, though. I bought a fancier electronic speed controller, wired it all up, programmed it, and all of a sudden, I had a running vehicle.
An Extra Cost
As it sits, you can order all of the parts to make this thing for around $800. I don’t really consider this an acceptable sum, but stay tuned on that front as well. As a caveat, a lot of this depends on where you live because of the shipping and taxes. Might be slightly less, might be slightly more. My price target was $600 because I felt like for an average person, that’s right at the limit of a significant sum to spend on a single hobby-related object. Before the VESC, a charger, and some other necessary accessories, it was around $700. So I got close.
That's just the way this sort of thing goes, though. A first prototype is always going to be expensive and have shortcomings. The math gets a lot better if I build more of these things. If, for example, I built two karts in the original spec, I would be splitting the cost of necessary accessories—like a charger—to one vehicle and shipping costs would be distributed to two vehicles. There are also setup costs associated with ordering unique parts from my supplier Oshcut, and they would’ve been split between the two karts. Two karts would’ve been around $600 each or less.
Driving the Kart
But now that the kart runs, let’s get to driving it. In terms of how well this thing works, here are a few videos. The first clip is my brother driving. The second clip is me when I first got it working. It even makes some organic EV noises I kind of like in this application.
I've done some testing and the top speed on level ground with me driving is around 15 miles per hour. I could definitely get going faster with a long enough strip of smooth concrete or asphalt—especially now that I've boosted the amperage delivered to the motor—but I value my life too much to take this out on an actual road. The hub motor is only 350 watts, less than half a horsepower, which means the performance isn't anything amazing, but it is actually faster than I thought it would be. You would be surprised how far this level of power really goes. It's not gonna pass on the Interstate, though.
I got it going fast enough to tip it over, fall off, ruin a pair of pants and injure myself. That should give you an idea of how fun this kart is. It's really fun.
Behind the wheel, you sit basically four inches above the ground, which makes any speed above 10 mph feel like a million mph. Likewise, the steering is very quick and tight, believe it or not. You can feel the chassis flexing under load while driving, which adds to the sketchiness, and it’s easy to determine the point when you’re right about to flip over. The result is that I can keep it right on the ragged edge for a long time. At least, until I have a lapse in judgment, which is how I ruined those pants.
Yes, there are some teething issues but they don't detract from the entertainment value. The chassis, for instance, needs to be more torsionally rigid. In some videos, I saw it bending in the middle like a popsicle stick during hard cornering. Heavy riders make this worse. Instead of the 1x3-inch extrusion, I should've really used a 3x3-inch unit, which would've added just $20 more to the total cost. This would increase the rigidity considerably and would make the seat mount a lot stiffer. It should also have an extruded front axle, like the main chassis spar, which would make that part more rigid and even slightly cheaper. The current bent steel front axle gets the job done, but for someone around 200 pounds, it’s at its limits.
The front wheels are also just not up to the job. Not only would it ride a lot better if there was air in them, but whatever they make these Harbor Freight solid tires out of is very cheddar cheese-like in consistency. I've only driven the kart probably five miles at an absolute maximum and they're already seriously worn down. You can tell they weren't intended for this.
The turning radius is also too large for a go-kart as well. This isn't a quirk of the steering angle, the kart is just long for what it is. The seat slides along the extrusion to accommodate a rider of any height, but I think I went too far with that. Making the wheelbase shorter would address this.
In terms of endurance, the battery lasts for 15 to 20 minutes at a 45-degree Fahrenheit ambient temperature. This is a lot better than I thought. I ran the thing around the parking lot outside my building for that amount of time to figure this out. As a tip, if you’re trying this at home, especially around an apartment complex: Your neighbors won’t know what to make of you when you do this. One of them came outside while I was setting it up and was like, "I'm...sorry?" Kind of a weird situation for her, I guess. She was very nearly speechless.
Range is about one to three miles depending on the weather and speed. That's only around 50 watt-hours per mile, which is actually really efficient in terms of energy used for transportation. Sure, an electric bike is probably a lot better. But bikes are not go-karts and they don't have steering wheels, so they're dead to me.
The Pros Weigh In
One of the more entertaining parts of this project was getting a few senior automotive engineers' takes on it. Before I had the motor working, I had the chance to show my progress to Tadge Jeuchter, the executive chief engineer for the Chevy Corvette, while I attended the first drive of the new Z06. He looked at the picture of it on my phone very carefully, looked back at me, and said with a grin, "It doesn't look very stiff."
Turns out, that guy was right. He then continued to point out every component on the Corvette that I couldn’t make myself or afford to order without specifying huge quantities from a supplier. A nearby cutaway car at the venue made this easier. “You can’t make this, this one was tough to do, this you definitely couldn’t afford…” Thanks, Tadge.
The C8 Corvette's chief engineer, Josh Holder, had a similar reaction but was also intrigued. It’s possible to get aluminum extrusions in large, very rigid sizes for not much money, so I joked that you could probably make a structural tunnel for a small mid-engined car out of one if you really wanted. Holder laughed, saying, "Yeah, you could! I've thought about it!"
That was pretty interesting. Makes me wanna go bigger.
First Prototype Final Thoughts
Ambitious plans aside, though, the most exciting part about doing all of this was watching the birth of a vehicle. I know it's corny, but just look at it! I made that. A working machine is now on this earth that wasn't before, and it all came out of my head and from my hands. The entire process was so rewarding. I do want to go bigger and make something with four wheels, but for now, I just don't have room in my apartment.
And before we get to four wheels, I have to perfect what I'm doing with three. Right now, this kart just isn't polished enough yet to publish the plans in detail. I've already identified some key weaknesses that will be easy enough to address, and when I do, those will be the blueprints I release unto the world so that truly anyone can build one.
Before I end, though, I want to call out a company called WizardPins. Now, enamel pins are not an important part of this project and are completely unnecessary to its functionality, but I thought I would add one anyway. For about $200, Wizardpins will make around 20 enamel pins for you in any design you want. You send the company a JPEG, talk back and forth a bit, and they send you back pins of it. Simple as that.
I mention this because I wanted to brand my kart. Cars have badges, right? I wanted one. Also, whenever I ordered parts from various companies, they would ask for a company name. It felt wrong not to have a name.
In order to remember a dearly departed pet, I named my company Obie Industries. Obie was often aggressive and not firing on all cylinders mentally. This stemmed from being abused by his previous owners. When he wasn't having an outburst, though, he was kind, obedient, protective, and all-in-all an ideal dog. We loved him.
Joking about his aloof demeanor, family members would often say that, actually, it was all an act. Obie ran a very successful multinational corporation called Obie Industries. In our heads, it made large charitable donations in his name, he would arrive at flashy venues via helicopter—piloting, naturally—and his vibrantly successful organization was involved in several fields of groundbreaking research of which he was intimately knowledgeable, including go-karts, of course.
I cooked up a logo, got my pins, and fixed one to the front of my kart. It just works. Even though v1 isn't perfect and I didn't hit my original price target of $600, this definitely won't be the last vehicle from Obie Industries.
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