After Gutenberg

Ebikes, i.e., bicycles with electric drive, a.k.a., diandong zixingche, need standard, low cost battery packs that are reliable, robust, and powerful. Indeed, this blog previously “called out” A123 on this issue. The Internet has been a-buzz GreenWheel-wize.

O.K., O.K., while this blog “calling out” anyone, is facetious artifice, nevertheless, 2 facts remain: 1) my physicist friend is putting a Bionx on her recumbent… and 2) Toshiba and Continental now are offering lithium batteries for electric vehicles. The latter indeed may have been an incentive for A123 to “put up” or “fold up”.

In a sense, the GreenWheel makes your bicycle a “through the road hybrid” when you replace a drive wheel with the Green Wheel. The designers created the GreenWheel by “enclosing a motor, A123 Systems batteries and a generator into a small aluminum pancake hub… Unlike conversions kits from the past, it forgoes running wires the length of your bike by incorporating the magic of bluetooth to control the twist-throttle.”

The GreenWheel is an add-on that provides electric assist to a human-powered vehicle. (Note the intentional use of the term “vehicle,” rather than “bicycle.” You could add a GreenWheel to human powered vehicle with more than 2 wheels. For instance, you could add a GreenWheel to a recumbent of a tadpole configuration (i.e., with 2 front wheel and 1 rear wheel. The vehicle then might look something like the award-winning, “Sipping Woodpecker“).

Writing for Autoblog Green, Domenick Yoney tells us that the MIT GreenWheel concept should have a bright future. He bases his prognostication upon a perceived demand from “a world-economy that can’t afford to buy cars the way they used to”, or never could. There are approximately six million bicycles made in China yearly, so the question is how many bicycle owners could afford and would choose an amendment to a bicycle with an estimated cost of “several hundred dollars.”

An electric motor developed by Wavecrest was no wider than a bicycle rim. The hub motor had regenerative braking and required no gearing.

While a pancake motor used to propel a bicycle is nothing knew, Lee Iacocca*, and replacing a bicycle wheel with a “fifth wheel” powered with lithium batteries is prior art, the batteries inside the wheel with the electric motor / generator does seem to be a novel configuration.

*Note: In 1999, Iacocca became the head of EV Global Motors, a company formed to develop and market electric bikes.

ABG reporter Yoney sees such converted bicycles as a “wonderful solution” for several cities that have expressed an interest in ride sharing programs. Hm, maybe? ABG reporter Yoney probably never has had a wheel stolen from a bicycle he owned, eh? Anyone know the current status of Intrago, an on-campus bike-sharing programs upon which this blog previously reported?

Over a dozen different configurations of the GreenWheel are scheduled to be tried and tested** by a variety of cyclists this spring. Once the the team analyzes their feedback, an ultimate configuration of power, speed and cost will be settled on and mass production will get under way.

** BTW: Hobbyists have been testing with A123 lithium battery modules for a while now. Since the motor can function as a generator, one might suppose that part of the testing will be without and with various ways to included regenerative braking.

Eric Bland got to test one such GreenWheel setup and wrote about it for Discovery News. “During a recent afternoon test ride around MIT’s campus, he found out that “a GreenWheel equipped bike is a smooth ride.”

Turning the handle mounted throttle, like any motorcycle, just a few small degrees produces a noticeable increase in power and a light electric hum. The handle-mounted throttle is connected wirelessly to the electric motor in the wheel.

The GreenWheel is also durable. The team estimates its range at 40,000 miles, or about eight years work of travel at an estimated 20 miles per business day.

“You’ll have to replace the bike before you replace the batteries,” Lin told Discovery News.

Typically, diandong zixingche (English: e-bike) riders lack NASA budgets. They want to start as cheaply as possible, so battery packs that swap quickly are still preferred over fast charging polymer, lithium-ion packs. This could change if the price per kW became affordable, either for nickel metal hydride or safe lithium batteries.

“Just take the wheel off, put a GreenWheel equipped wheel on in its place, plug it in and it should work just fine,” said Ryan Chin, one of the GreenWheel designers. “The whole thing has been designed so all the parts except the throttle are enclosed in the wheel.”

From the outside, the GreenWheel has the radius of a small dinner plate and is about 2 inches thick. Inside the aluminum frame sits the three major GreenWheel components: an electric generator, batteries and an electric motor.

For now, installing GreenWheel on your own does require a moderate level of technical knowledge or a trip to a bike shop. The GreenWheel can be installed on any bike frame or wheel size, but the original spokes have to be replaced with shorter spokes. Michael Chia-Liang Lin, a master’s student at MIT developing the GreenWheel, called his parents in Taiwan, who own a bike shop, to figure out how to respoke the wheel.

Under its current configuration, a bike powered solely by a single GreenWheel (front, rear or both wheel can be equipped with a GreenWheel) has an estimated range of 25 miles. Pedaling the bike doubles the range under electric power, provided the rider isn’t traveling at the nearly top speed of 30 miles an hour. The bike can be charged by pedaling or by plugging it into the electric grid.

Bottom line: This would seem to be a pretty neat way to add electric drive to a bicycle. Whether large scale production will occur may depend upon how cheaply the product can be made compared to the growing selection of electric cycles made in China, Taiwan, Thailand, and Vietnam. (Note: Sometimes the distinction between an ebike and electric scooter / moped can be nominal, since pedals sometimes are included simply to satisfy classification regulations; no one in their right mind would want to pedal very far given the weight of such 2-wheel electric vehicles.)

BTW: Not all ebikes are made in Asia. There is a least one North American company, Opti-Bike, “the best electric bike in the world”, that makes a top-end, electric bicycle and there are some home garage efforts by enthusiasts.