Posts Tagged: BionX motor


27
May 2010
by don

Dawn of the (U.S.) cargo bike revolution

[NOTE: I originally posted this article on May 27, 2010.  Since then, new information has become available.  I edited this on August 24 to incorporate some of the new developments.]

The title of this post might be a tad premature, but today I’m feeling a little more optimistic than I have in recent weeks.  That’s partly due to encouragement from my readers (you are a wonderful bunch!)  And perhaps some of the credit goes to a break in our Seattle rain that is allowing work to proceed on the solar panels being installed on my roof this week (soon I will be motoring up the hill using electrons harvested very locally).

But the biggest boost in my outlook came from news that two of the biggest names in cargo bike manufacturing — Kona and Yuba – are offering electric assistance as a pre-built option for their bikes.  Regular readers of my blog will know that this is a development I’ve been waiting and wishing for, and I think it signals the beginning of a new chapter in the annals of this kind of transportation (at least in the U.S.)

Why is it significant?

First, customers will no longer have to build these bikes themselves.  That requires either mechanical ability or a good bike mechanic and some extra cash.  But the process isn’t streamlined: which motor do you use?  Where do you mount the battery?  Are the specs on the motor a good match for the loads on the bike?  I’ve read several blogs where the build process took months to complete.

One can assume that the bike manufacturers have matched an appropriate motor to the bike.  If there are issues with the bike, there is a single contact, rather than wondering if the problem lies with the bike, the motor, or the installer.  To date, electric cargo bikes have been one-off custom builds, and there is no easy way to leverage knowledge or share solutions.

Economies of scale will reduce prices (both of the new bikes are significantly less expensive than mine), and competition will keep those prices within reach of people who need an alternative to a car for financial reasons.

So here’s a quick comparison of the bikes, with mine thrown in for context:

  Kona Electric Ute Yuba elMundo

Rans Hammer Truck / BionX
Price $2,599 $2,297 (includes tax and shipping!) $3,887 = $1,997 (bike) + $1,890 (BionX)bags/runners/deck not incl.
Motor 250W front hub 500W front hub 350W rear hub (BionX)
Links http://www.konaworld.com/bike.cfm?content=electric_ute http://yubaride.com/yubashop/28-e-mundo.html http://www.ransbikes.com/Hammertruck09.htm

http://www.cycle9.com/c9store/electric-bicycle-kits-c-5/bionx-pl-350-rear-hub-motor-kit-p-48

When I originally wrote this article, I included a row in the table above listing the carrying capacity of each bike.  Since then, I have become concerned about the ability of cargo bike brakes to stop loads that approach the carrying limits of the bike.  Yuba has actually removed any mention of carrying capacity from its website.  In my opinion, that is the responsible thing to do.  There is already a tendency for enthusiastic cargo bike promoters to put very large loads on these bikes and post photos for bragging rights.  Even though it’s fun, I don’t think it’s in the long-term interest of cargo biking to promote unrealistic or unsafe behavior.

Since I wrote this article, there have been further developments for the Ute and elMundo, and there is a new bike coming from Trek.  You can read about them here.


14
May 2010
by don

The perfect bike

After months of grey skies, the sun has finally returned to Seattle.  If biking in damp weather is fun, biking on a clear spring day is nothing short of euphoric. Our area is blessed with snow-capped mountains, lakes, abundant greenery, and flowers.    It is so much easier to appreciate this on a bike, I am again pondering what it would take to get more of my neighbors on bicycles.

As I see it, there are three parts to the equation:  better hardware, better infrastructure, and a shift of expectations that allows people to consider alternatives to the car.  Given some months of experience with this bike, I’m ready to start imagining what improvements to bike hardware could expand the biking experience to more people.

Average the effort

To my mind, there should be a nice middle ground between a manual bike, where all of the energy comes from your muscles, and a moped, where none of the energy does.  It would be cool to pedal at a constant, comfortable rate no matter what the terrain.  When you’re going uphill, you would be taking energy out of the battery, and when you’re going downhill (or flat at less than maximum speed), you would be putting energy in.

On my bike, I still crank the pedals pretty hard going up the hill, even though it’s nothing compared to when I turn the electric motor off.  Then I coast down the hill, recovering a little energy due to regenerative braking, but I could do more if I were actually pedaling.  I don’t pedal because the hill is too steep: I would start going uncomfortably fast.

More power

I can ride up our hill at about 10 miles per hour unloaded, or about 5 miles per hour with a passenger.  However, I wouldn’t mind going a little faster and putting in somewhat less effort.  Perhaps the BionX motor isn’t the ideal choice for this hill, but I love its quiet operation.  It emits a very low hum under the largest loads, but it’s not a sound most passersby would notice.

Reduce maintenance

Although our cars need occasional maintenance, it’s amazing how reliable they are.  The weak part of my bike seems to be the gears: I’m still missing a few that I could probably recover by doing some adjustments to the derailleur.  It’s kind of a pain to do it myself, and I don’t want to take it to a bike shop, so I just live with it.  But I really wish I didn’t have to deal with gears at all — I want an automatic transmission like my car.  I want to pedal at that nice comfortable rate and have my bike figure out how to apply that energy to the task of moving me and my stuff forward.

The perfect hill-climbing bike

The perfect bike for our hills would feed energy from my pedals into a continuously-variable transmission, combine it with energy from the electric motor, and scoot me forward at 20 miles per hour regardless of the pitch of the hill.  However, that transmission sounds complicated and expensive, and possibly not reliable.  Instead, maybe I should have a powerful motor driving the bike by itself, and my legs just turn a generator that adds charge to the battery.  I know that won’t be ideally efficient: converting mechanical energy to electricity and then back to mechanical energy will come with a significant tax.  More electricity will be needed from the plug to compensate.  However, I’m already accustomed to recharging my battery in order to go anywhere, so I don’t think this is a showstopper.  Then my friends can put in whatever effort they want.  If it’s a hot day and they don’t want to sweat, they could ride the bike like a moped without putting in any effort at all.  Such a bike would work for people of all fitness levels.

But I like the idea of pedaling not only to contribute some of my own energy to the task (thus improving fitness), but it’s also a nice control system.  Pedal faster to accelerate, slow down to go slower.  That seems more natural than twisting a handle bar grip like a motorcycle.

Keep dreaming…

I would like to experiment with the bike I’ve described, but the first challenge is finding a pedal-powered generator suitable for mounting on a bike frame.  It’s hard to find a manufacturer with a product like this, because generating power with leg muscles is a pretty discouraging experience.  First you need a heavy flywheel to smooth out the effort.  Even then, most people who try it find that it takes a huge effort to generate a few cents worth of electricity.  This mirrors my experience.  The three cents that I spend to fill up my bike’s battery delivers a huge amount of power to my bike’s wheel compared to what I can do with my legs.  

If any of my readers knows of a leg-powered generator that might work (smooth operation but not too heavy), let me know:  don “at” mycargobike.net

What do you think?  Is there something I’ve overlooked, or do you have different ideas about how a powered bike should work?  I would love to hear them!


6
May 2010
by don

Video of Rans Hammer Truck electric cargo bike

If a picture is worth a thousand words, I’m guessing a video is worth at least a hundred pictures.  I’ve been wanting to make a video showing the bike in action for months.  Now that I have, it won’t win any awards, but hopefully it will give you an idea of how the bike works and how it sounds (silent motor, squeaky brakes!)