Quote:
Originally Posted by STR8OUT
moar pics... where is the drive??
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that's all i have at the moment. real camera is up north with the girl, and cell phone camera doesn't take good pics up close (doesn't really take good pics from afar, either
). the motor is within the front wheel's hub.
Quote:
Originally Posted by dmpi
Man that is so cool! The way the motor is packed on the hub, suggests that it must have some pretty high torque. How long does the batteries last before it need to be recharged? How much weight do you think you added to the bike?
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yeah, the torque is quite high, as is power: i've seen 1300W peak so far on a steep hill. 1 hp = 750W for reference.. i have a home made torque arm in place: a 6" 10mm crescent wrench secured to the front axle flats and the fork using a cunning assortment of 2 hose clamps and a ziptie...
i use about 15-20 Watt-hours (Wh) per mile the way i ride, which includes pedaling, of course! the battery is a 48V 12Ah lithium. Wh = V * Ah, so the battery theoretically has 576 Wh. in reality i'll probably get 500 Wh out of it, so 20-25 miles is the range before recharging.
added weight is a lot, on the order of 35 extra lbs. you don't want to do this to a bike you like for being a bike, if that makes sense.
here's the power and torque curves for the motor in question (Crystalyte 407) hooked up to a 48V battery with a 35A controller:
that i'm seeing peaks higher than the graph indicates that i'm going over 35A, i think.
how to interpret the graph: to push a typical rider and bike along at 25 mph on flat ground takes 500W more or less, with aerodynamics (tucking), tire choice and pressure, and other factors making this a very ballpark figure. notice that this motor is just above 500W at that speed. this is why top speed on flat in a tuck is right around there.