Thursday, January 6, 2011

Safety Razor Safety Advisory Report

So it's been a month since I butchered a child's Razor scooter and shoved a electric bike motor system into it. Let's hear some results!

I am able to use it for inter-campus transportation with about 50% capacity drain for a full day.

That's acceptable. Especially since it is probably mostly burst amps from accelerating. Voltage has yet to drop below nominal 22.2 (for a 6-cell lipoly). I still regularly monitor the pack for increased volume, but nothing vile has arisen. The picture above shows post-charge results. We have a 66% drain over an extended run time (I had group projects across campus that evening). You'll have to excuse my camera. No flash superimposed the words "END" and "BAL" to create the illusion of "BAD" on the LCD screen.

Over a period of time, I discovered my ground clearance to be steadily decreasing. My predictions have been reaffirmed. The amount of metal removed from the original frame, combined with the hastily designed frame extensions drastically reduced the integrity of the structure. I disassembled the frame this holiday break and discovered the fracture points to lay just as I had predicted: the region where aluminum and polycarbonate met.

All of this could have been avoided by starting with a single piece aluminum frame extension. Thankfully, I am still a ULI, and speedy metals is having a 10% holiday discount until January 31. Therefore, bring in the upgrades!

From the image, you can see the back end remains virtually the same. I rotated the motor mounting holes so that the centerline from the motor shaft to the wheel deadshaft were in line. Originally, the sprocket would rub against the spacer with left from some interestingly deep erosion marks as illustrated in the picture below. Undamaged spacer included for reference. I hope you know what a hex bolt is supposed to look like.

The majority of the changes were made to the front half. This iteration does away with the original scooter frame. It was far too troublesome modifying the frame to the design and it bore little fruit other than comedic value. This body is serious business. Slots and tabs everywhere. The accessible panel has been moved from the bottom to the top. This is because repeated ground scrapings sheered screw heads which made it a pain to disassemble. Speaking of bottom plates, a UHMW skid bar will be added to take the blunt of aggressive gutters and sidewalk ramps. On top of all that aluminum will most likely be a sheet of 1/16" garolite. Just something to cover the large gaping service channel and be pretty. If it is garo, I might even consider laser engraving a graphic into the center of the deck. Gettin' fancy now...

Of course, this frees up about 2-3" of space in the scooter body, not to mention the extended width and height. This means I can opt for a BIGGER BATTERY or protection to my current pack. Both would be nice, but I may push for the larger battery in preparation for the next advancement in campus transportation: MTD (to be described in detail later).

Lots of great material coming up (but its late, and im lazy).

1 comment:

  1. Sounds super exciting! Hope the revisions go speedily!