| ||organisation: Randy Draper – EV Motors|
type of biz: solar-powered electric bikes
distribution: in progress
what: reliable, efficient, affordable: a simple, long-lasting solar powered electric motor attached to an ordinary bike frame.
The bikes can go "up to 30 miles per hour, create no pollution, are totally silent, can go up any hill, are simple to repair, and the batteries can be recharged with energy from two things we have an abundance of here on Maui - sun and wind," explains Randy Draper, until yesterday an ordinary bike rider, and today the inventor of a new artisanal but efficient cycling system that has focused a lot of attention on him.
In his workshop located in his home in Napili (Hawaii, USA) you can see the solar panels and windmill he set up on his roof about sixteen years ago, and which he says have saved him over $200 a month on his electricity bill ever since. At the time it cost him about $3,000 to get the system fully operating, but he says "it would be cheaper now because some of the components cost less."
the story: Randy grew up playing with nuts and bolts. His father was an electronics engineer who made the first starter motors for Boeing's jet aircraft engines and later developed guidance systems for the aerospace program while working at Vandenburg Air Force Base in California. His grandfather owned a bike shop in Salt Lake City, Utah, and later a washing machine and lawnmower repair shop in Provo, Utah.
eureka! Randy was given the opportunity to make a bicycle for Maui's annual Cycle to the Sun, a race billed as the world's steepest, climbing non-stop from sea level to the very top of the volcano Haleakala. Using an unusually efficient 750 watt brushless motor he designed himself, a modified three-speed hub shifter from bicycle component maker SRAM, and a 48-volt nickel-zinc Evercel battery pack, his full-suspension mountain bike is a test bed where total over-the-road efficiency is the guiding rule.
technical sheet: while most familiar commercial electric bikes use a 250 to 400 watt motor and lead acid batteries, Draper wanted more power for hill climbs, better efficiency at a wider range of speeds, and much greater range. His 7 lb. motor design, just as efficient as a generator, has been used in prototype boats and bikes. The race would have been impossible to complete in for any commercial stock e-bike. Not only is the road too steep, with an average grade of 5% and long stretches over 15%, it is also far too long.
Most e-bikes would have trouble completing a fourth of it before the batteries died. Even with better batteries the motors are not designed for long efficient runs at 750 watts and would overheat. But Draper figured that with his efficient set-up and a new type of EV battery with nearly twice the power of lead acids, the distance might just be within reach. With assistance from Bob Ketell at Electricab Energy in California, the U.S. distributor of Evercels (industry leader in Ni-Zn - rechargeable battery - technology), Randy got four of these batteries and grafted them onto his specially prepared motorised mountain bike.
interested? Randy started his small enterprise, EV-Motors, for clean efficient transportation: 1-3 Kw Brushless BLDC motors for full suspension MTB bikes, or any other bikes, scooters or boats with Lithium Polymer batteries or any other batteries for faster and longer run times.