Vehicle / welding / electronics / controlled silliness

Drift Trike

Electric drift trike. Fabrication, motor mounts, controller wiring. It has to make a you grin while going sideways, even better if your children think it's "sick".

Test run Cool welding shots

Finished electric drift trike photographed on grass. — Finished 'enough' to hand over to the test driver

BUILD SPEC 72V / 3000W

Frame: The front end is an old BMX, cut up and reused. Everything behind it is steel box section and angle, welded up in the workshop.
Motor and drive: A 3000W brushless DC e-bike motor kit, chain drive to the rear axle. Rated to 6600rpm, so geared it works out about 35mph but lots of torque.
Controller and battery: 72V 20Ah lithium pack with the kit’s matching brushless controller. The main isolator is a 125A two-pole DC miniature circuit breaker — a proper DC-rated breaker, thirteen pounds, which is the best-value part on the trike.
Wheels and tyres: Go-kart wheels at the back with PVC pipe sleeved over them. The whole trick is having no grip at the rear and all of it at the front. It's tricky to find the pipe though
Build time: A few weeks across the summer holidays, built with the kids.
Cost: £399 for the battery, £180 for the motor kit, plus steel and small parts. The donor BMX was already scrap.

What went wrong

A big problem is where you put your feet. The instinct when trying to stop is to put your feet down and I can see that would lead to breaking an ankle. Needs some thought.

What I would change

Build a proper foot platform across the front, so there is somewhere obvious and comfortable for feet to go and no reason to reach for the ground. Everything else can stay exactly as it is. It is definitely fast enough!

Payoff

The acceptance test

Go, turn, slide, and smile.

Family workshop

Lincoln fitting the wheels

Learning

Tapping a thread

First signs of life

Motor electronics on the bench

Motor, chain, controller, wiring and display, run together on the bench.

Wiring

Making up the high-current wiring

Controls

Bench-testing the control box

Green welding

What the welder actually sees

Shot through the fixed grade 10 welding filter - so we can see the arc, puddle and filler rod at once. Puddle size, travel speed, how far ahead of the bead you look. Comments are disabled :)