Electric Vehicles, Blog

Note: I’ll say this before I dig too deep into the content of the blog. This morning I logged in to find that my WordPress password had been changed (MD5 decryptor couldn’t decrypt it unfortunately), and once I manually reset my password in the database, different parts of the dashboard were broken. I doubt the blog broke itself. So, to whatever bot or being did this:

Every step you take, I’ll be watching you.
Every single day.
Every hack you make.
Every script you change,
Every code you break, I’ll be watching you.

Oops, got carried away.

During the last week or so I’ve been excessively interested in portable and quick “personal electric transportation”. Oh dear, I’ve gone an made an acronym in my first sentence… The idea is to use these small vehicles in areas with high pedestrian traffic, on trips where walking would take too long, and have a range that allowed for multiple such trips on a single charge. The most ideal form for such a vehicle that comes to mind is the scooter.

The scooter in the picture is a 100W “Firefly” scooter, purchased from Giant Tiger years ago for $100. It came stock with 2x 12V, 4.5Ah batteries hooked in series (24V), a 100W motor, and as far as my research has shown, a 150W controller. It has 125MM rubber tires, and a rear drum brake. In this photo, I have removed the plastic base/cover, change the stock seat for a more comfortable bicycle seat, and in the large black bag, instead of having 2 batteries, there are 6. Total of 13.5Ah. Plenty of run time, and the controller can suck all the current it needs to get me going.

In terms of performance, it is a bit limited. I would say I could get to about 15km/h on this. Not terrible, but because the scooter makes so much road noise, it is slightly embarrassing to slowly crawl by the people who point and laugh. Now, if it went 25km/h plus, that would be something else.

And that is my goal. I’ve been researching different motors and controllers, and I have a few possibilities.

  • Replace the controller with something more powerful (risk of damaging motor).
  • Replace motor with something more powerful (would require some structural modification, risk of damaging controller).
  • Replace both motor and controller with more powerful versions (structural modification, but ability to maximize power).

Most electric scooters use brushed DC motors. These are your standard, two wire motors. Hook up power and go. However, a lot of scooter modifications I’ve been seeing online are making use of brushless motors. These motors have 3 wires, and require a special controller. This isn’t your plug-n-play motor anymore. The controllers will send out pulses of electricity to the motor across any pair of the 3 wires in order to create rotation. There are no brushes, so the controller is in charge of switching polarity in the coil.

However, this is where it gets interesting. One project, by Jerome Demers (http://www.jeromedemers.com/blog/2010/05/top-speed-with-my-scooter/), makes use of brushless motors to attain mind-boggling speeds of over 40km/h! This is the kind of Ludicrous SpeedTM I would like to reach.

The batteries are stored in a camcorder bag, crammed in nice and tight, and “secured” to the scooter using a bungee. It doesn’t leave much leg room, but the trade off is range and performance. Right now, I feel the problem with this scooter isn’t torque, it is speed and RPM. When I put it at full throttle, the tire will hit a maximum speed (duh). However, even when I am riding it, I am able to hit this maximum speed as well. Another thought I had was to simply gear it differently, make the gear on the motor bigger, or the gear on the tire smaller, in order to reach higher speeds.

Anyway, this is enough for one post. There are so many things to consider for something like this, and it makes you wonder, “maybe I’m better off simply building a scooter from the ground up.”

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Monday, July 12th, 2010 electronics, projects

1 Comment to Electric Vehicles, Blog

  • Michael says:

    dude that’s actually really cool… and I think that building the scooter its self would prob end up result wise the best, one with slightly bigger wheels lul

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