Sprockets.ControllerThe Motor
OwnerXavier Hanson
Owner's Other EVSears Free Spirit
LocationGainesville, Florida US map
Email email image
VehicleSears Free Spirit Step-Through Bicycle
A chain-driven electric bicycle, with a small motor. Nothing fancy, I was going for a practical vehicle rather than a speed demon.
MotorUnite Motor MY1016 Permanent Magnet DC
350 watt continuous motor.The motor is bolted on a standard bicycle rack.
Drivetrain#25 Chain, 11:54 gear ratio. I didn't feel like doing any machine work, so I found a ready-made sprocket that would fit where a disc brake normally would. I bought a rear wheel with the standard 6 holes for a brake plate, and simply bolted the sprocket on. I got that sprocket from electricscooterparts.com, it was originally intended for the "Lashout" Electric Bike.
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
Heater90+ degrees of carcinogenic Florida sunshine.
InstrumentationSpeedometer
Top Speed20 MPH (32 KPH)
Cruises at 10-15mph. All this is WITHOUT PEDALING. It once got to 24 MPH, but that was a freak incident.
AccelerationKinda on the wimpy side, but I ain't Steve McQueen!
Range5 Miles ( 8 Kilometers)
Probably more than 5 miles. Still being tested.
EV Miles
Current:25 Miles (40 Kilometers)
Seating Capacity1 adult
Curb Weight60 Pounds (27 Kilograms)
It's not as heavy as the Ezip electric bike I have.
TiresStandard bicycle tires.
Conversion TimeMany months of planning & scrounging, many weeks of building & cursing , a few minutes of blissful riding.
Conversion Cost~$300, but that was mostly from experimentation, in the end, you could probably build a bike like this for about $200.
Additional FeaturesA very comfortable throttle, 40A fuse, and a "Kill Switch" on the handlebars (always a good thing).
4-13-2011:
DO NOT TRY TO BUILD A BIKE LIKE THIS WITH AN ALUMINUM RACK AND WITH SUCH A LOW GEAR RATIO. THE FORMER MAY BREAK AND THE LATTER MAY LEAD TO YOUR MOTOR OVERHEATING. A GREAT DEAL OF CURRENT WILL BE WASTED THAT WAY.
I am leaving this bike up here for reference, and in the hope that others may learn from my mistakes.
MARK II is by far the better bike.
What follows are my original observations...
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The motor can get very hot! I gave it a lot of room so it would cool down. It rattles a bit, but I think that can be fixed by adjusting the chain tension.

*In order to prevent motor damage, one must pedal to 10MPH before engaging motor.*

I dreamt of converting a car to electric, but I decided to build an electric bicycle since it was within my budget/knowledge-range. The hardest part was probably mounting the motor and making sure that the sprockets were aligned properly. This EV was constructed out of a bike a neighbor was throwing away, parts scrounged from another neighbor's busted electric scooter, and components for electric bicycles that must have been intended for the Chinese market. This website really helped me to brainstorm, and I hope more and more people build their own EV's.

Update 7-19-10
I've installed the chain for the pedals, and after pedaling up to 10mph, I engaged the motor. I was able to ride 2 miles at 10mph without overheating! I even did some speed tests at 20 mph on a very slight decline.

Update: 9-11-10
The Saddlebags are not secure. I'm planning on modifying the bicycle so it can keep the batteries safe and watertight. Someone suggested changing the gear ratio for more torque, so I might consider that as well.

Update: 9-26-10
After a week's worth of discussion with more experienced ebikers, I found that I would need a 1:10 ratio in order to work efficiently. I looked at all the alternatives open to me, and I decided to replace my motor with a brushed hub motor. That is such a radical change that it will be displayed as another project on this great site. Stay tuned :)
*NONE* of my leftover parts will be for sale. So please don't ask. I got most of my parts at very decent prices at tncscooters.com and electricscooterparts.com

code by jerry