electric assist

[ccf]

I'm interested in retrofitting my wife's Sofrider with an electric assist. We'd like it to be easy to swap the non-electric wheel in and out so that she doesn't have to carry the extra weight on flat rides. So I figure maybe an e-assist for the non-drive-wheel would be best. But don't really know much about it.

Any suggestions on how to get smart on this?

Thanks,

-Cliff

 

[SamP]

I'm hardly an expert, but I've done some (online) investigation in the past.

First: The Endless Sphere Forums is probably the biggest DIY ebike online community. You'll probably want to spend some time there.

Here's one vendor of kits that seemed to be recommended on Endless Sphere when I was skimming through it some time ago: EM3EV

I was going to write some more, but perhaps it would be better to leave that to someone with actual experience.

 

[mzweili]

Any suggestions on how to get smart on this?

have a look at this site:
http://www.goldenmotor.ca/products/26-Inch-24V-Front-PRO-902-Conversion-Kit.html

 

[super slim]

If you want the Electric drive to assist in hills, I would ONLY go with a bottom bracket motor like the Bafang BBS-01 350W 36V, 3.8 kg, from EM3Ev of Hong Kong, so it uses your rear cluster to give 15% gradeability, WHILE still operating in its max power (66 crank rpm) to Max efficiency (78 crank rpm), using the 8, 9, 10 rear cluster gears to choose the max speeds of 9.5, 12.3, 13.7, 15.7 , 18, 20, 21, 22, mph. Electric assistance is meant to cut out at 15 mph.
http://em3ev.com/store/index.php?route=product/product&product_id=167


http://wooshbikes.co.uk/?motorcharts
This link gives a good comparison of the drive-ability of the different E Motor types.

The 3.8 kg BBS-01 motor could be mounted on the BB of the Moving BB, but you will have only one chain ring, and the front will flop around with the added 3.8 kg.
http://em3ev.com/store/index.php?route=product/product&product_id=167

If you have a Softrider V1.0 with a 135 mm rear axle, then the BBS-01 motor and chainring, NO cranks, can be fitted to the frame BB, and drive a rear wheel with 9 speed cassette, using a thumb throttle and rear derailleur thumb shifter on the left handle bar, and a twist and thumb shifters on the right for the pedal power.

If a Softrider V2.0 with a 100mm rear axle, then a geared 250W wheel 4.0 kg, with a one way clutch, and a built in controller to simplify the wiring, would be the better option, but would only be able to climb a 10% gradient at 6 kph (3.5 mph) , and have a 50% reduction in battery life as the motor is only efficient at 20 to 22 kph (12.5 to 13.7 mph). You need to only use the geared motor above 6 kph, as the three narrow plastic and some metal gear teeth brake if starting from a stop.



LiFePO4 36V 15 Ah batteries can be recharged 2000 times compared to Li-ion (500 charges) and Ping Batteries have the best Battery management system according to high power (3,000 W hub motors) of Bikeforums.com, and Endless-sphere.com
http://www.pingbattery.com/compare/83/82/81

A Ping battery needs to be used inside 1/3 of a rear rack bag (Topeak Ex) for protection, and to see the charging lights for each cell, while charging .

Some water bottle sized batteries have NO battery management system , so very short life!

 

[ccf]

Thanks for all of the input. After researching some more, I think what we want is a pedelec (i.e., proportional assist), not a throttle-controlled assist. But I'd like to put it on the rear (non-drive) wheel. Pedelecs appear to be the norm in Europe. Any input on where I could find a torque-controlled pedelec for the non-drive wheel in the US?

 

[mzweili]

I believe the ''pedelec'' feature wont work on a non-drive wheel. The same applies for the ''Copenhagen Wheel''.

 

[ccf]

I believe the ''pedelec'' feature wont work on a non-drive wheel. The same applies for the ''Copenhagen Wheel''.

Looks like the Electron Wheel should work on the non-drive wheel of a Sofrider.

http://www.electronwheel.com/

Anyone have experience with it?

 

[super slim]

I have looked on the Internet and can not find ANY actual users reviews of the Electron Wheel, max speed 20 mph, with 24V 10.7 Ahr (256 Wh) battery
At 20 lbs (9.0 kgs) for the wheel, you will definitely need an air shock (Manitou Radium R 165 mm compressed, 38 mm movement) for the rear suspension to handle the extra 8 kgs of unsprung mass when going over any bumps.

I had a 7.5 kg 20" Golden Motor Magic Pie 3 direct drive(first installed on a 20" trike) on the back of my Softrider V1.0 (135 mm rear), and even with the Air shocks, bumps were a LOT more noticeable.

http://dillengerelectricbikes.com/e...bike-kit-samsung-power-13ah-by-dillenger.html
This 350W geared hub motor front wheel + wiring, weighs 4.5 kg 9.9 lbs, with a 7.1 lb 36V 13Ahr (468 Wh) battery.(82% more capacity, and range, than the Electron Wheel battery)
This system has a simple Pedelec system that senses crank movement, with 9 levels of motor torque assistance , from 10% to max motor torque, irrespective of wheel speed.
These simple pedelec systems have approx. 2 to 3 seconds delay for power on or off, but the switched hand brake levers, instantly cut the power, and the thumb throttle can instantly apply 10% to 100% power.
This geared hub motor has a Max speed of 20 mph, so its most efficient speed (81% efficiency) would be approx. 17 mph, and max power at 15 mph.
Below those speeds, then the efficiency drops off to 50% or less and a LOT of heat is created in the motor, and the battery range is reduced dramatically.

http://www.ebikes.ca/tools/simulator.html
This is a very good tool to see the effects of throttle, motor controllers, battery capacity, on the speed, range and efficiency under different conditions.

A geared 26" hub motor of 15 mph max speed would be better suited for hill climbing, as closer to your climbing speed of ?? mph!

 

[SamP]

I believe the ''pedelec'' feature wont work on a non-drive wheel. The same applies for the ''Copenhagen Wheel''.

I believe most pedelec use a torque sensor somewhere in the crankset, which may be adaptable to a CruzBike with some work, but certainly isn't as plug&play as the Copenhagen wheel was intended to be (for most bikes). This is probably why most pedelec kits are generally available to bike builders and not as end-user installable kits.