5 ms·
New electric bike drive system requires no chains or belts, ride-by-wire
- the_gastropod 5y agoThis says it's 5% less efficient than using a chain? Can that be legit? That seems awfully efficient for the double-conversion that needs to happen from mechanical => electrical => mechanical.
- foxyv 5y agoModern electric motors and generators are pretty efficient. Just a lot heavier.
- akomtu 5y agoI think the catch is that it'll be getting less efficient with time: those rechargeable batteries love to degrade.
- tonyedgecombe 5y agoThe generator and motor won’t though which is what is effecting the efficiency.
- akomtu 5y agoPerhaps they are a lot less than 95% efficient, then? Otherwise we could install this system into cars and ditch half of the mechanical parts. That would be a revolution.
- tonyedgecombe 5y agoThat is how some trains worked: https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/g/Gas_turbine-electric_locomotive.htm https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/g/Gas_tu... Also the range extender in the BMW i3: https://discover.bmw.co.uk/help/used/how-does-range-extender-work https://discover.bmw.co.uk/help/used/how-does-range-extender...
- daggersandscars 5y agoThey don't state what chain system they're comparing it to. Given the coverage in the article, their base case may be a three+ wheeled cargo bike with a long / complex chain run. In those cases, a complex chain run results in significant energy loss compared to a regular two-wheeled bicycle. Back when I bicycled, I first noticed this when I added recumbent bicycles / tricycles to my "fleet". The two wheeled recumbent had a long chain and guide wheels. The three wheeled recumbent had a long chain, guide wheels, and guide tubes.
- ncmncm 5y agoIt doesn't say how they get the power to the hub motor. But I realize I don't know how that is done in regular ebikes. Through opposite ends of the axle? And, the axle is electrically two pieces?
- foxyv 5y agoOn our E-Bike it's a wire that enters the center of the non-rotating axle which connects to the internals of the motor. https://images.app.goo.gl/N1S8keh18fapj6jY9 https://images.app.goo.gl/N1S8keh18fapj6jY9
- carl_dr 5y ago> If the rider pedals hard enough to create excess energy (more than is required to power the motor at the current speed), that energy is dumped into the e-bike’s battery to be used later. I’d want that to make the bike move faster. That behaviour is going to be really unintuitive. Unless I’m misunderstanding? I have an ebike for windy/lazy days, and the assistance cuts out at 25km/h. I can still go faster by continuing to pedal sufficiently hard. I’d rather do that and sacrifice regenerated power than be limited to 25km/h.
- tengbretson 5y agoSince the only way to impart energy into the drive wheel is via the 250w motor there's really no way to do what you are asking for without overloading the motor.
- karmakaze 5y agoA mechanical linkage might be more powerful for a given weight. Less messy maintenance though.
- tonyedgecombe 5y agoChains are a weak point on my e-bike, I only get about 1250 miles out of each one.
- seltzered_ 5y agoThere was another company that's been playing around with the idea of chainless series hybrid bicycles for a few years called bike2.dk (an older video: https://www.youtube.com/watch?v=4JKOKpg21dQ https://www.youtube.com/watch?v=4JKOKpg21dQ ) - they seemingly haven't shipped a product yet five years later. Beyond that think there's also been experimental covered 'human-powered' vehicles done similarly. It may work for some specific commuter usecases but have had a hard time being convinced it replaces a typical consumer e-bike - they assume it's been initially charged. The interesting part though is the possible component/maintenance reduction if things like regen braking really works or there's more ergonomic/accessible/multi-person form-factors introduced.