Make Your Old Bike Electric For Less Than $100, With This Clever Gadget

Your beat-up clunker will fly.

A typical electric bike might cost $2,000. But a simple new attachment is designed to turn your beater from Craigslist (or the fancy road bike that you already own) into an electric bike for around $100 or less.


“There is, that we’re aware of, no low-cost alternative for turning your old bike electric,” says Per Nilsson, a spokesperson for Semcon, the Sweden-based engineering company that designed the new gadget. “We saw an opportunity to develop a product that is inexpensive, low weight, easy to switch, and has enough power to support more bikers.”

Other kits made for converting bikes into e-bikes are made for longer trips, which makes them both heavier and more expensive. Realizing that most bike rides can be shorter (most bike commutes in the U.S., for example, only last about 10 minutes), the engineers were able to design a very small, detachable battery.

At the beginning of a ride, cyclists pedal on their own, which also helps reduce the size and cost of the attachment. “We optimized the motor to kick in when you need the support the most –between seven and 25 kilometers per hour,” says Nilsson. “This made it possible to make the engine smaller.”

Unlike some other conversion kits–like electric wheels–the attachment is also easy to remove so it won’t be stolen. The battery, attached with a magnet, snaps off to go in a backpack or inside for charging. The attachment can also easily be moved to another bike.

Because the simple design uses an Arduino computer with Wi-Fi, it can also be used to connect with navigation apps, anti-theft tracking systems, or to share data about a ride. Despite all of the features, the prototype cost just €100 to create, and once it’s in production, will likely cost much less.

Semcon has considered crowdfunding the design, but plans to talk with other companies and investors first. Once it’s ready to buy, it’s likely to make a difference. In the U.S., one out of every three people owns a bike, but few ride regularly; people with e-bikes are much more likely to commute to work. For couch potatoes, e-bikes can help people actually start to exercise (even though the bike does some of the work, it’s still a way to get healthier). Soon that will be possible without shelling out hundreds or thousands of dollars.


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About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.