Project: Converting a Push Scooter to Electric via Power Drill

Back in July, I hit upon a somewhat ridiculous idea: why not transform my standard push scooter into an electric vehicle?

I primarily utilize my scooter to navigate around during autocross events while working the course. While it serves its purpose, I found myself feeling envious of the other participants zipping around on modern electric scooters, especially given how affordable they've become.

I could have just bought a pre-made electric scooter. However, I already owned a scooter and didn't see the point in owning two, as one would inevitably just gather dust.

The Foundation

The base for this project was a Razor A5 Lux. This model was absolutely not designed for electrification, but by leveraging my welder, 3D printer, and a variety of components sourced from Amazon, McMaster, and Harbor Freight, I managed to cobble together something truly impressive.

Technical Specifications

The vehicle is front-wheel drive (mimicking my Civic) and is powered by a high-torque Hercules cordless drill.

"The drill is fairly loud and possesses an excessive amount of torque, requiring it to be operated on the lower speed setting."

Performance Metrics:

• Top Speed: $\approx 10\text{ mph}$ (with rider onboard).
• Incline Performance: Slows down slightly on hills, but the drill handles the load effortlessly.
• Range: A $5\text{Ah}$ battery provides roughly $2\text{ miles}$ of travel.
• Efficiency Calculation: $\text{Range} = \frac{\text{Battery Capacity}}{\text{Current Draw at Full Tilt}}$

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Engineering & Mechanics

The power transmission system is designed so that the front wheel can still free-spin when the motor is inactive. This is achieved through a combination of a keyed shaft and one-way bearings.

Power Flow Diagram

The Throttle Challenge

Relocating the trigger to the handlebars proved more difficult than expected. While opening the drill was straightforward (the trickiest part was the left-hand bolt securing the chuck), the trigger assembly contained a surprising number of wires.

To make this work, I had to:

1. Cut each individual wire.
2. Extend them using 12awg and 18awg wiring.
3. Install professional wire loom. $\rightarrow$ Decided to embrace the "jank" for now.

Handling Note: The trigger is incredibly sensitive. Because it wasn't designed for a vehicle, there is almost no way to "feather" the acceleration. Consequently, the scooter often performs a brief burnout before it gains enough momentum to move forward. My current strategy is to provide a few manual kick-pushes before engaging the drill.

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Custom Fabrication

I decided to over-engineer the front wheel by using a 3D scanner on the original scooter.

Wheel Construction

The assembly consists of three printed pieces:

• Wheel Hub/Spokes: Printed in ASA for strength.
• Tire: Printed in TPU for grip and flexibility.

The two halves of the wheel are joined by 10 M6 bolts and nuts, with 5 keys (one per spoke) for stability. To prevent the TPU tire from slipping on the ASA wheel, I utilized a "squish fit" design and integrated internal teeth on the mounting surface.

Bill of Materials (BOM)

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Final Build Checklist

• 3D Scan original wheel
• Print ASA wheel and TPU tire
• Modify drill trigger wiring
• Install one-way bearing assembly
• Weld mounting brackets
• Install wire loom (Pending)

Final Verdict: In terms of raw cost, I didn't save a dime compared to buying a commercial electric scooter. However, the process of building it was an absolute blast.