3kW Electric Scooter

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[Exco] had been playing around with the idea of building an electric scooter for a while now, and over the holidays he decided to just do it.

Similar to the motorized long board we shared last month, this scooter makes use of an RC hobby motor — in this case, a 63mm 3kW brushless outrunner (for a RC plane), coupled with a 100A ESC. He bought the scooter (“kick board”) off eBay for cheap, and spent a few days in the machine shop modifying it. It has better wheels now, and custom milled aluminum brackets for mounting the motor. The drive system uses a belt and pulley with a sliding rail to provide tensioning.

To power it, he bought a bunch of 2.5Ah, 18V LiPo packs on eBay originally from a Makita drill set. He then sorted out the cells, removed the dead ones, and soldered everything together for his own Frankenstein pack to balance them. The final configuration features twenty-one 18650 lithium cells. He even shrink wrapped it, which makes it look relatively professional!

It’s controlled by a push-button potentiometer hooked up to the ESC. Theoretical top speed is about 27km/h @ 1285RPM, and they managed to get it up to 25km/h in a real test. There’s more info over at the Endless Sphere forum, and we’ve got two test videos for you after the break.

[Thanks Momo!]

Comments

  1. Hack Man says:

    Reminds me of combat robot style (think Battle Bots) drives and motors.

  2. static says:

    Would I be mistaken if I’m skeptical of the implied 4 hp. produced by such a physically small motor? Even if it’s it’s for brief peak I can’t see how such a spec could be useful, other than for marketing. I’m understand James is reporting what he was given, and I’m not blaming him for anything.

    • Colecoman1982 says:

      The thing about RC airplane/helicopter motors, as far as I’ve always understood it, is that they CAN produce the rated power output but in doing so they are running much closer to their absolute physical limits than motors in most other industries. As such, it’s much easier to burn them up by accident and they aren’t expected to have as long of a service life.

    • Debraj says:

      The RC motor rating is based on the assumption that they are “air over” design. Even in HVAC application, the motors which drive the fan directly (and hence gets cooled), have higher ratings. I am not sure as how this motor will behave in scooter, which do not have forced cooling of motor.

  3. Hack Man says:

    He also makes porn.

  4. Ace Hole says:

    I’m pretty sure neither that belt nor that wheel can actually take 3kW … the belt is going to stip pretty quickly.

    A bike chain would be a better choice, but would probably also not last very long.

  5. strider_mt2k says:

    Cool sticker collection.
    Good luck with the project.

  6. Scott says:

    Nice project. Scooters can be difficult depending on your parts available. I built one with a “300W” brushed DC motor I overvolted to ~32V running off LiPos and a homebuilt speed controller. When it wasn’t smoking FETs it’d do ~37km/h. Anything more than a KW on these things is generally overkill – you can’t accelerate very fast on a push scooter safely without losing control in one way or another, generally by popping the front wheel due to the high torque. Gear down more and you could go a lot faster with that power. Though, I have melted wheels before on mine. It’s a tough design game!

  7. exco says:

    Well the max recorded power to the motor was ~1 kw (38A @ 28V (-voltage drop)).
    The belt wore out because my first motor mount bent.

    I’m upgrading from a T5 to AT5 belt and think it will hold longer than I’ll be interested in riding it ;-)

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