Electric bikes are expensive. Even if you buy the cheapest electric bike you can find on deep discount at walmart, it costs $300. (Formerly $400 before they deeply discounted it.) I decided to build my own out of surplus parts and things I could buy at the local Ace Hardware for less than $300. (Mostly, for the fun of the build.)
So, I bought a surplus motor controller, handlebar mounted throttle, and a 250 watt electric motor. I bolted the motor to the front of my used $20 bike, built a battery holder out of PVC pipes, and made a vacuum formed cover.
Not counting the (high) cost of labor, here is my bill of materials:
Item – Cost
24vdc 40A motor control – 32.95
Two 12v 5AH sealed Lead Acid Battery – 32
250 watt PM motor – 25
Used Bike – 20
#25 Roller chain – 10
Twist Grip Throttle – 12.75
Consumables (solder/wire) – 10
PVC Pipe Joints (4 elbows, 2 t’s) – 4.74
90 tooth sprocket – 4
Four 10” bungee cords – 3.79
Bicycle wheel hub – 3.5
Four M6 hex-cap bolts – 3
5 pack 25amp fuse – 2.99
Auto Hitch power supply connector – 2.34
Five feet PVC Pipe – 1.5
Blade Fuse Holder – 1.5
Four Fender Washer – 1.2
motor controller case – 1
#25 Roller Chain master link – 1
Four 3/16 quick connects – 0.2
Two M10 1mm pitch nuts – 1.4
Ebike Total: 174.86
Next projects: Adding lights for night biking, and solar charging.
Related posts:
9 comments ↓
[...] case I need to commute home after dark on my electric bike, I added a front headlight (5 watt MR11 halogen) and a rear tail light (Red LED tail light for [...]
nice work dude!
I’m planning to build an electric bike, i learnt a lot from ur blog.
i have an advice for u, try mounting one more of the PVC pipes on the other side of the motor, it’ll make the cycle look more symmetrical.
[...] since I mounted an electric motor to the front wheel of my bicycle I have been keeping a plastic bag over the motor with a clothespin [...]
Hey Jay,
Did u ever experience any slippage(excess) with the #25 roller chain, don’t you think #25 is too small a size for such a task.
Taja,
It’s only a 250watt (rated, running closer to 350w) motor. I never had a problem with the chain (although I sometimes had problems with the mechanical linkages I had built).
Jay
How fast does this bike go without over doing it.?
Does the motor get hot ever?
John: Top speed without pedaling is around 10 mph. I’ve never noticed the motor getting too hot.
Jay
how did you decide how big or small to install your sprocket ?
John, I ordered the largest sprocket my surplus supplier had, and the smallest sprocket the motor came with. It’s hard to gear an electric motor too high for a bicycle ;> You could use a smaller sprocket for speed, especially if your motor was stronger than my 250 watts, but I was trying to maximise torque, and wasn’t looking to go terribly fast.
BTW- Thanks for the URL to an alternate (but slightly more ghetto) sprocket/wheel mounting system:
http://www.youtube.com/watch?v=k3YFmtb6JEA&feature=email
Leave a Comment