This Instructable provides an overview of the design and construction of a small electric go-kart or microkart with brushless motors, lithium batteries, independent suspension and a composite deck chassis, built from new components for under $1500. By keeping the design as light as possible, this microkart maximises performance from 6.5hp and its tiny size exaggerates the 40mph top speed.
SKIP TO BUILD STEP 1 - DRIVE TRAIN or continue reading below for more background info about the project.
My overall goal was to produce an electric go kart for under $1500 that showcases current motor and battery technology, is suited to on or off road use, great to drive and challenges a few of the standard approaches to kart design along the way.
Some friends are building electric gokarts by taking a sprint kart (fixed gear racing gokart) and replacing the 2 stroke engine with an electric drive train. This is a quick way to make an electric kart, but unless you already have a racing kart you need to first buy a kart which would blow my price goal. I also wanted to further develop the go kart concept in a few other areas including size, chassis, suspension and independently driven wheels.
Size - to keep weight as low as possible, provide greater options for racing in carparks and indoors and make for easy transport in the boot of a car rather than a trailer, this design miniaturises the already miniature, hence the name microkart. This will extract maximum performance from the small electric drivetrain.
Chassis - structurally racing gokarts are flexible enough to lift or at least reduce the pressure on the inside rear wheel when cornering to counter the effect of a solid rear axel. In this design the rear wheels are driven independently with a motor for each wheel so the chassis will not need to flex for cornering and all four wheels can remain on the road. In addition the electrics are mounted inside the chassis instead of on top for protection and a cleaner look.
Suspension - go karts don't usually have suspension which is fine on a smooth kart track, parking lot or in a warehouse, but to find more places to drive it, improve performance and to provide a smoother ride off road, the microkart is designed with suspension. While it does appear to go against one of the principals of the go-kart which is keeping the design as simple as possible, the challenge is to do it cheaply and simply using easily available components.
Independent drive - ultimately I want to produce a 4wd gokart to maximise acceleration on and off road with each wheel independently powered by its own electric motor. To reduce costs and complexity (avoiding CV/universal joints at the front) I will be driving the rear wheels. Independent drive should extract more grip than a solid axel as well as saving the weight of the axel. It also opens opportunities for the future for developing a traction control system.
So on with the build....