Timeline

Feb 2017 - Current

Project Background

This project was spawned by a desire to make my daily commute to class faster. Being a poor grad student, paying for a campus parking pass was out of the question. I could have bought a bike, but when I found an old 80s kick scooter on Craigslist, I couldn’t resist the temptation to build something ridiculous.

Project Description

The build is fairly simple: a brushless hubmotor+wheel rescued from a dumpster replaces the rear wheel of the scooter. A cheap Chinese ebike motor controller and a trio of old NiCad drill batteries make up the power system. Paired with a handle throttle form Amazon, and I was good to go after a wee bit of hacksawing. Given that most of the parts were either found, Craigslisted on the cheap, or donated by generous well-wishing friends, this build was kept under the $50 mark.

Version 2 of this scooter replaced the drill batteries with 4 lithium-iron-phosphate battery packs very generously donated by a friend. These batteries were production prototypes of devices meant to be drop-in replacements for gel lead-acid batteries in backup applications. Unlike the old drill batteries, these are not as severely affected by the Minnesota cold, and they have a much higher energy and power density. I get 5Ah@56V with this battery arrangement, instead of <2Ah@48V. With the new pack, I got greatly increased range and acceleration and slightly increased top speed. Charging is accomplished using a Meanwell LED streetlight power supply (which does the constant-current regulation the batteries need to not get angry).

The most recent set of improvements added a speedometer, bell, tail lights, and a 12V LED headlight powered from the 56V battery pack through a buck converter.

Believe it or not, I used to ride this horrible thing to school nearly every day (except in winter, mostly). It has a top speed of a little over 20mph and a 16 mile range. Planned improvements include a less terrifyingly bendy chassis and perhaps some better brakes. I’ve purchased a bike disc brake conversion kit and an adapter ring that should fit the hubmotor, so all that’s left is to modify the frame to enable mounting the calipers!

Project Links

• Github repo for original build
• Github repo for speedometer
• Github repo for new chassis design (mostly CAD files right now)

Acknowledgements

Thanks to Hanna Lin for help with building, and to Dane Kouttron for donating parts (and for carrying some really weird looking stuff through airport security screening).

Project Photos