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E-WAW, a bio-electric hybrid

Geplaatst 8 jun. 2011 10:09 door Brecht Fietser   [ 8 jun. 2011 11:12 bijgewerkt ]

On the hybrid front we're now offering a custom mix of light and reliable stuff from Crystalyte and Cyclone. At 2.2 kg, the 250W Cyclone motor is reasonably light - and silent - but when it drives the pedals instead of the rear wheel it is powerful when you need it. By using the gears it can operate at its optimal efficiency, even when you're going up a steep hill or accelerating to cruising speed. Our customers report they can hold 50km/h speeds on human power relatively easy, as long as the motor helps for acceleration.

It's not a weak electric car but a true human-electric hybrid setup where the electric assist enhances the performance of the bio-engine. The human motor is actually quite good at converting biomass into work: about the same efficiency as a good combustion engine and much better than an electric system. But we suck at handling peak loads. In this graph we see how radically our endurance drops when power demand increases. (definitive article by John Tetz)

Adding up to 200 Watts of power during peak demands, transforms an average rider into a top athlete. As the assistance is only intermittent (hills, acceleration, merging in traffic) we only need a tiny battery. In this way we enhance the cycling experience without falling into a feedback loop of power and weight.
Acceleration and climbs don't wear the rider out as quickly anymore, which means the better part of the rider's energy is available for the long, constant stretches that make up the majority of the ride. Here the rider is hardly bothered by the 4 to 5 kg weight increase of motor and battery.

Where our system really outshines the more powerful and heavy hub motor setups, is its lack of resistance at higher speeds. Hub motors are okay on electric bicycles, but fail at the extended speed range of a velomobile, lacking power in ascents and resisting high speeds by inductance. We do however use the Crystalyte battery and a modified Crystalyte thumb throttle for greater reliability.

But you all knew that, of course. Let's see where the really advanced cycling technology is at, as seen on Spezi.