E-Bike

Starting with the most substantial I should probably start with the E-Bike. This project began probably about 2 months ago, but has been mental designed over the last year or so. It all started when I stumbled across an electric motor from a razor scooter that was sitting unused in a fellow Engineer's apartment. Online they were going for around $30 plus 5lbs shipping, but for $15 this one was mine.

Anyway onto the actual bike...

Most of my projects are based on a low income college students budgets so the design is based almost entirely on what I have. In this case that happened to be a circa 2000 NEXT Krusher stunt bike that I could not give away on craigslist. The motor sits where the rear brakes once were (who needs rear brakes anyway) and is welded to a plate that is bolted to the lower fork. Proper gearing is achieved through a double gear reduction system that utilizes the shaft and bearing that the pedals were once mounted too. Cogs are salvaged from dairy farm equipment, one side is thinned on a lathe to fit bicycle chain while the motor side uses standard #40 roller chain. Custom bushing all around.


Here's a better view of the bike from the opposite side. I was originally using only the smaller (rearward) 12v 7Ah lead acids but voltage depression is kinda a little harsh when you are drawing ~20A through them so I added 2-12v 12Ah lead acids that I got used from a friend for free. Rack in the back is also a freebee. It needs to be modified a little bit so I can get rid of the 6v battery "spacer".

 What bike is complete without some serious lumens? Bike comes custom with a Cree XR-E headlamp, heatsink and LED were stripped out of a previous maglite mod so that's what the cardboard spacer is for. Thermal insulation is nearly irrelevant because that LED would take quite a long time to heat up that chunk of Al past 150 degrees F.

 Completed headlight. Maglite reflector works great and the lens is just some clear pop bottle cut into a disk since the glass lens for the maglite doesn't quite work.  LED and Driver is courtesy of Dealextreme. Nothing like free over month shipping from china! 

I built a custom motor driver for the bike but it is not pictured because it kinda sorta exploded. Should get around to repairing that in the next few days so its description comes up next.