Ryobi Bike

I built an electric bike!

Way back when, an electric bicycle kit was my gateway into the world of building electric vehicles. I recently got back in to electric bicycles for two reasons. One is that an injury makes it hard for me to pedal a standard bike without a fair amount of pain. Two is that I bought a Ryobi electric chain saw which runs on a 40V battery!

For years, I’ve had an old 500 watt, 36V hub motor and controller kicking around, which was given to me by a friend. It seemed to me that the expensive part of an e-bike is the battery! Hmm… Couldn’t I just use the 40V power tool batteries I already had to power an e-bike?

So, I started building it, mounting the motorized front wheel into an old bicycle frame. I figured that the specs on the 40V batteries were really about right for a bicycle. Researching what I could on them, and what the motor needed, it looked like a good match.
On top of that, I stumbled on a project by some engineering students out east who did the FULL ENGINEERING process of what it would take to create a bicycle powered by tool batteries. In the end, they chose Ryobi 40V batteries!

I had already worked out exactly what I wanted to do for the bike, but the student’s engineering just confirmed it!

Even better than that, they also shared some of the files they created for their project. I had purchased a 3D printer not too long ago. Just being able to download a pre-designed mount for the battery and print it out myself was fantastic!

I Printed the battery mount, and wired it up to connect to the controller. I also designed and printed a mount for the motor controller to go on the upright tube of the bike. I made the sides of it hollow to hide the extra wires which I wouldn’t need.

The bike works great!
It cruises (without pedaling) at 20 MPH, which is the typical legal speed for this type of vehicle in most areas.

Range is 12-15 miles per charge of a 4AH, 40V battery. I have 3 of these batteries and could always carry a spare, but most of my trips are less than that anyways.

The bike is fun to ride, and by taking pressure off my knee, means that I actually CAN ride a bike pain free!

Information from the engineering students at the University of Pittsburg is here: LINK HERE.

Happy bicycling!
-Ben Nelson

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