Saturday, June 8, 2013

More Guavascooter: Speed and Distance Testing

Today I took a little adventure to visit my good buddy Chris down over at Bolt IO, a new shiny hardware startup incubator located conveniently close to campus (and chinatown!). Needless to say, I'll be visiting often.

This trip, for this time anyway, included the use of the T, so I had to park my scooter somewhere on campus. When I returned, I visited the ME graduation banquet and then returned home for a bit. Later, I left my housing again for a meeting with my PI over in building 35. Nowhere throughout the day did I charge guavascooter. This was a perfect additional data point to hopefully better estimate traversal distance. Here is the route:

A total of 3.5 miles. using the numbers from last post, we expect a battery expenditure of about 1170 mAh per mile. However, today's route only used 3170 mAh, which means approximately 905 mAh were expended per mile. This results in a projected distance of 7.6 miles. Lets say 7 miles just to be safe.

The second test that day was the speed test. I selected the section of road between Amherst Alley and Mass Ave as the trial space. This is a roughly half-mile section of road.

My timer showed I made the trip in approximately 1 minute and 52 seconds. This meant that my scooter maxed out at about 16 miles per hour. That's pretty slow for my tastes considering Razor Wind was estimated to run at 30 miles per hour and Razor Reloaded was to run at ~25. This is not a major issue but if I decide to address it I could change the sprocket ratios or select a new motor.

Thursday, June 6, 2013

Cambridge and Guavascooter

I made it alive to MIT. Today marks one week of life up here. One week of life walking about because my latest scooter  just came today. Discussing the name with Charles, we decided a more fitting name for it was "Guavascooter", as an extension of Melonscooter except using the guava sized SK3 motors.

Without delay, here comes testing.

Tonight I drove this route to MITERS from my temp housing at Tang. Its about 1.68 miles as indicated by the picture above.

This route expended 1967mAh of battery capacity. From a 6900mAh pack, this means I could run this route about three times safely assuming voltage drop does not fall below 21V (ESC cutoff).

Tomorrow, I will determine the max speed of this scooter via time trials down Vassar street. More to post later.

An additional note, I am no longer using the esc in Guavascooter. The current ESC is a elifebike esc, which Charles and I will touch on later in the coming weeks. Cheers!