Start Small … The E-Kart
When undertaking any new project, advice usually goes to the tune of “start small”. So I did.
I had seen many electric karts on youtube, and got the all familiar “I could do that!” feeling.
So I did.
Introducing the “E-Kart” (I know, original…)
Before I go any further, perhaps an introduction. I’m Dave, I write for EV Gearbox Magazine, along with the creator of Gearbox Magazine Brian. A big thanks again to Brian for letting me basically hijack his idea to promote EVs :)
Now, electric go-karts, and by extension electric cars are not a new idea. Thats one reason that makes it so easy to DIY. That and the advent of the internet. Go-karts are a great stepping stone, as are servicing fork lifts or golf buggies, or heck even RC cars, they can all foster an interest in electric transportation. Search youtube for electric go-kart, absolutely everyone is doing it :) (and electric cars for that matter!)
My kart consists of a $50 chassis Craigslist find, all it needed was a new rear axle and bearings, and some air in the tires. (and new brake lines after I broke one…)
The motor is a 7 inch Hyster forklift motor, I believe it is the traction motor from a 2000lb forklift. 24v Series wound DC.
Some welding and minor fabrication took place on the frame for extra supports and battery enclosures, for that I am thankful to a colleague at work with a good amount of welding experience.
That funny looking blue thing is the contactor, an Albright 400A 28v (it still holds contact at 24v) its basically a huge high-current switch. The controller gets its initial power via a “precharge” resistor that bridges the contacts on the contactor, effectively bypassing it and limiting current to charge the capacitors in the controller. Then the on-off switch tells the controller to close the contactor, then its game on.
The controller is a 4QD 300 amp 24v-48v its actually popular with large scale park railway operators and those crazy people who build battle-bots. (Fun Fact: both the controller and contactor where manufactured in the UK :)
The batteries are Sealed Lead Acid Werker 12v 33ah, wired in series for 24 volts. I used AWG 6 to wire everything together, and I think the smaller wire for the controller wire harness is AWG 26, its all from an old TV :)
As of yet I don’t have the controller’s throttle POT (potentiometer/varistor) hooked up to the gas pedal, it has mechanical rotation of about 300 degrees, and no spring return. I just put a small handle on it and keep my hand on it all the time.
Soon I hope to wire in a proper throttle and attach it to the cable from the pedal; it will have about 50 degrees travel, so the pedal will probably move about .5-.75 of an inch. Either that or I can get a linear POT which will do the same thing.
Enough of the boring details, more photos!
the day I got the motor mount :)
fitting the new rear axle
Yes, I'm definitely grinning in this photo.
I figure the range of this thing to be between 5 and 8 miles, acceleration is probably 0-40 in under 5 seconds. The total cost was just over $1,100 and time to convert was just under a year. The next one will be bigger. :)
A quick note on charging, the two batteries are removed from the kart and charged in parallel using a 20 watt solar panel, via a Brunton solar charger, it probably takes a good 6 peak sun hours to get them nicely charged from something like 11.9v to just under 13v Thats another area for future upgrades, more solar FTW.
