Electric Knee Scooter
Knee scooters are always fun to play with so why not make an electric one?! This is a fun and simple project that utilizes an old motor and VESC I had sitting around. For power, I’m using 2 Ryobi 18V drill batteries in series to make a 10s pack. Theoretical top speed is around 21mph with a full pack not accounting for any loss in efficiency. Most of the modifications were designed in SolidWorks and 3d printed on my Bambu Labs X1 Carbon. The motor is mounted via a laser cut steel plate that is welded to the frame.
The scooter uses a 170KV motor with a 1:6 5M HTD belt reduction. 30A fuses protect the batteries since I still need those for my power tools!
The battery adapters I found off of Amazon are held in with a printed part that holds the batteries at a slight angle away from each other to allow for finger clearance to remove the batteries. They are clamped into the print and screwed in from the inside. I printed a rough drill guide with oversized holes so alignment isn’t super critical. Screws prevent the battery adapters from pulling out when removing batteries.
Testing the fit in a section (blue) with some old filament before committing to the full pulley (white). Torque is transferred through interfacing geometry from the pulley through the spokes in the wheel. The large diameter and amount of teeth engagement made me feel comfortable printing the final pulley out of PLA.
