EVplasmaMan

After a long wait I was finaly able to weld my A123 cells like I should have done from the start. Thanks to Richard for the use of his welder and thanks to Bill for telling us how to use it. Here are the results.

Here is a quick and dirty post of all my photos from the scooter project. I will put up a blog post explaining them some time in the near future. If you have any questions please post a comment and I will incorporate the answers in the post.

About a year ago I decided I hated parking at the Caltrain station; it was always full, you had to park far away from the platform and it cost $20 a month for the privilege. It was time for another solution. I live about a 15 minute walk away from the station so a scooter is a perfect alternative to driving/walking. The other issue was what to do with the scooter once you were at the station, I decided to make it small enough and light enough to take with me on the train. This created a bonus, now I could ride from the station up in SF to the office!

Me testing my scooter, by testing I mean goofing off & pulling wheelies

With those requirements set I started to look for components starting with the batteries. The batteries are the key component to any vehicle since they are such a determining factor, dictating the general size, shape, weight and power of the vehicle. After surfing the web for about 2 minutes I came to a conclusion that lithium batteries were the ultimate solution for my scooter. With there high power density, light weight characteristics I could have a scooter with a good range but still be light enough to be picked up and carried, something that is lacking with scooters on the market today.
More on the batteries later…

A group of 48 A123 cells ready to burn rubber

On to the motor! A friend of mine is a fan and competitor in a miniature version of battle bots. While visiting his house one day he showed me one of the motors he was using to drive a large drum with a lot of knarly looking spikes on it designed to chew up an enemy robot. Looking at the puny size of the motor I asked him what kind of power he could get out of it. Turns out that it’s a brushless out runner motor with a whopping 600 watts of power! I asked if they made anything a bit bigger… a search of hobby-lobby.com revealed a motor about the size of one of those small cokes you get on an airplane with a phenomenal 3000 watts!!! That 4 HP! I had found my motor
More on the motor later…

The Motor next to its custom gear box

Now to the frame. My first idea was to take a razor scooter frame and just slap on a motor and batteries and go, but at the end of the day I decided to build my own frame for two main reasons. Reason one: I wanted to be as light as possible but I also needed a bit more room for the battery pack then what was available in a razor. Reason two: I have been learning how to use Solidworks 2006 and wanted to put my skills to the test. Being able to go through several revisions without building a single thing is a god send for any engineer.

The frame mostly assembled

Next time I will be talking about each of these parts in more detail. I’d appreciate any feed back or questions.
Till then,
Jos Goble

This is the “final” CAD of my scooter. The whole process of designing took a total of about 2 months. This time was filled with research on components and creating those parts in digital space. It took several revisions but I was able to start machining out the components on my friends tiny CNC mill and slowly piece them together.

Here I am cutting out one of the two latching brackets. This was a time consuming process because cutting stainless steel requires a slower cutting speed and finer passes. The result was beautiful.

Here I am the day of the EV rally putting the frame together. Events such as this are great for getting out of gumption traps and pulling all nighters.

This is the motor/gearbox assembly in the frame with the chain hooking around the rear sprocket.