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Old 05-09-2008, 02:08 PM   #1
shikataganai
Scooby Guru
 
Member#: 92634
Join Date: Aug 2005
Chapter/Region: RMIC
OMGHi2U my electric bike

August 24, 2012 update reflecting its v2.0 rebuild with a 9C 2806 hub motor and a 48V 35A regen-enabled Infineon controller:

Quote:
Maiden ride has been accomplished in grand fashion: 8.2 miles, 4.6 Ah, 27.8 Wh/mi. Max speed without pedaling, wide open throttle was around 27 mph on flat ground. With me pedaling along I could get it up to 30 mph. Comfortable cruising speed was more in the range of 23-25 mph while pedaling along, throttle part of the way open. Max indicated power from the battery to the controller (so less at the wheel due to motor inefficiency) was about 1600W at 27 mph. Max regen coming down from 25 mph was around 550W, decreasing as speed decreases. Overall I regened 6% of power input on my errand run today.

Original post below:

Quote:
i built myself an electric bike. why, pray tell, given that i'm still sound of mind and body, at least by most accounts? the answers are speed and convenience. the added power lets me add things that are useful but which i wouldn't put on a road bike, such as full fenders, a solid rear rack for panniers, and a heavy internally geared hub.

electric assist is the difference between a) cruising up a decent grade at 18 mph in street clothes and shoes with cargo, contributing moderate pedaling effort and b) busting one's butt in clipless pedals to ride a road bike up the same hill at 8-10 mph. top speed on the flat with me tucking like a goon and not pedaling is right around 25 mph.

it's really quite fun, and, with the racks and such, useful.

technical details (again from the original build):

Quote:
Novara Transfer bike from REI with a Nexus 7 rear hub
Crystalyte 407 front hub motor in a 26" wheel
36V-72V 20A pedal-first controller mated to a Crystalyte twist throttle
Cycle Analyst - Direct Plugin model
48V 12Ah LiFePO4 battery with battery management system (BMS)
Tubus Cargo tubular steel rear rack rated for 80 lbs iirc
Novara Safari waterproof panniers
the electric bits were all sourced from http://ebikes.ca/ . they ran about $1600 including shipping, with the majority of the cost ($900) being that fancy lithium battery. lithium isn't cheap! true story. the bike itself ran $510 on sale at REI, and came stock with the fenders, rack, and even a front wheel generator/light setup that i sold for $100, for a net cost of ~$2100.

i don't anticipate this being a financial windfall - i have a bus pass already, and previously was commuting the vast majority of the time on my road bike, the bus, or some combination thereof. however, i do think this will allow me to reduce gasoline usage even more, and it will allow me to make my commute to the hospital at all hours quicker and with less effort if i'm tired, and that's worth it to me. also note that my electricity is 100% renewable thanks to an opt-in program through seattle city light...

on the other hand, if you're hard core enough (or your city is flat enough!) to get by on a fixie, cross bike, or regular roadie without electricity, then bully for you.
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Last edited by shikataganai; 09-01-2012 at 11:27 AM.
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