Handle barsThe Motor
OwnerXavier Hanson
Owner's Other EVSears Free Spirit Bicycle
LocationGainesville, Florida United States map
Email email image
VehicleSears Step-Through Bicycle
A simple electric bicycle using parts scavenged from previous projects and fellow experimenters.
It uses the same frame and controller as the "Electric Donkey" I built previously.
MotorHeinzmann Permanent Magnet DC
400 watt continuous brushed DC Hub Motor, taken from a 24 volt EVG Ebike.
DrivetrainThe hub motor is part of the wheel. The Heinzmann motor is geared, and not a direct drive hub motor.
It's built like a tank!
ControllerYi Yun YK42-2
Batteries2 Enduring CB12-12, 12.00 Volt,
Sealed Lead-Acid (SLA) batteries. 12 Volts and 12 AH/20Hr Rating.
System Voltage24 Volts
Charger HG6S240160
Henguang Power 24v 1.6AH Rate
HeaterBall of Hydrogen fusion 92 million miles away.
InstrumentationSpeedometer
Top Speed13 MPH (20 KPH)
Not a speed demon. She just chugs along.
If I helped it, it could easily go faster, but why hurry :)
Downhill speed is as fast as gravity can take you.
Acceleration0 to 12 MPH in 6 seconds. WITHOUT pedaling.
Doesn't sound like much? On a little old bike like this, that is plenty!
Range10 Miles (16 Kilometers)
At least!
Seating Capacity1 adult
Curb Weight0
60+ pounds
Less than 200 lbs with me on it.
TiresStandard Bicycle Tires
Conversion TimeLots of time. This was a labor of love. I wanted to *build* this thing, and not just get a kit off the shelf.
Conversion CostWhen all is said and done, you could probably build this machine for $200. But that could double if you do as much "research and development" as I did :)
Additional FeaturesA half-twist throttle, 40A fuse, and a "Kill Switch" on the handlebars (always a good thing).
A Voltmeter has been put inside the battery case, so that state-of-charge can be monitored easily.
I wanted to build something strong and reliable. So after learning that the gear ratio I had on my old machine was inadequate (And finding that the rack I had used was not quite strong enough to handle the motor), I decided to try a Heinzmann hub motor.
They seem to have a reputation for reliability, and I was lucky enough to find one at a very good price ($100 including shipping) from a fellow experimenter on an ebike forum that I frequent.

Update 10-16-2010:
First test ride! This thing is great! I wasn't going for speed, but rather torque. Traveled a good 10 miles without a noticeable decrease in performance. I help it a wee bit up hills, but strictly speaking you don't have to >:)

Update 12-3-2010:
I've taken the old girl out every now and again to do my 7 mile commute. Occasionally I have to nurse her, but I haven't had any catastrophes. It's getting too cold for lead acid around here now, which is fine since it's now the perfect temperature to go human-powered!

Update 12-10-2010:
I'm planning on making a modification that will allow me to use the Heinzmann's overheat-safety feature. Once I get that up and running, I may run this beast at 36 volts instead of 24. This may require a new controller, but I'll see what I can do with what I have lying around.

Update 4-13-2011:
This same motor and controller has been placed in another bike frame. It now looks a bit nicer, and is more comfortable to ride. The speed and all the specs are the same. Eventually I may experiment with it a bit more. That will probably be a whole other project.
As for over-volt modifications, this controller has capacitors capable of handling 50 volts, so it can run on 36V ONLY IF USE THE HEAT SAFETY FEATURE ON THE MOTOR. I'll see if I can get that up and running.

code by jerry