Pedal-Powered Generators

[Eric Kaplan]

So, some of you know that I am still involved in an art and music festival in Atlanta each year.  I have been a volunteer for the Atlanta Dogwood Festival for over 8 years, including 4 years on the Board of Directors.  Presently, I am a member of the Advisory Board of Directors, and return each spring to Atlanta to be part of the event Staff.

The Dogwood Festival has an Internationally-recognized Green Program and Eco-Village, and is recognized as setting the standard for how large festivals should minimize their impact on the environment.  Previous and ongoing projects include recycling, use of biodegradable plates and plastic-ware, biodiesel-fueled generators, and outstanding community outreach by environmental organizations to the patrons attending the festival.

One of our goals for the 2013 event is to establish an installation of stationary exercise bikes connected to generators to create power from human energy.  The power would be captured in some form of battery system, and would be used to supplement the biodiesel generators in a specific location, such as the main concert stage.  There are "commercial" versions of these pedal-powered generators available from sources such as:

          http://pedalpowergenerator.com/buy-bicycle-generator-assembled-pm-motor-pedal-power.htm

          http://www.pedalpowernyc.org/

However, we are hoping to avoid the cost associated with buying commercial products like this, as well as keeping as much of the development local to the festival.  To that end, I have reached out to Atlanta's Makerspace, Freeside Atlanta, to see if they have any interest in being a partner in this project.

I don't know what their capacity would be, but if it turns out they cannot participate, would anyone here be interested in developing the design of the system?  OMG could develop the plans, and the Dogwood Festival could take the plans and have the units produced locally.  I could probably arrange for at least one person to garner a free trip to Atlanta in April as a result.

I know there isn't much direct benefit to OMG, but if anyone is interested in seeing a project like this be developed, this would be a great opportunity.

--

Eric J. Kaplan                                       

• ekap...@gmail.com
• www.ejk00.smugmug.com

[Stephen Beck]

I have a lot of experience with both power generation (its my job) and bicycling (my second biggest hobby), but don't have a whole lot of time to donate to such an effort.

Would such a device use something like automotive alternators or something along those lines? We can get piles of them cheap from local junkyards...

I think it sounds like a cool project and would be willing to help...

[Kevin Fusselman]

Automotive alternators might be overkill, as an average cyclist can only make around 1/4 hp (200w). I wonder if there are efficiencies to be had, using a smaller generator, closer to its limits... Hobby-grade brushless motors come to mind...

[Ben Hutcheson]

The only problem I can see with hobby brushless motors is that you're going to generate 3-phase AC.  I'm not sure how much effort it would be to make that usable.  What about brushed motors?  That'd give a nice DC output.

[Eric J. Kaplan]

I assume that any output is going to go into a bank of batteries, and then through an inverter to standard AC power. If that helps any. 

Sent from Eric's iPhone

[Stephen Beck]

a 50 amp automotive alternator is only capable of putting out around 600 watts max...smaller ones are made, but they are readily available, cheap, already have a pulley for a belt drive, have fully internal voltage regulation circuitry and put out DC power at a level perfect for charging 12V batteries. Additionally they are built robust enough to install into an application where they can be used and abused and keep on working (strong frames designed for mounting and they can tolerate being wet, getting poor cooling, etc). I would urge that it be considered. We don't need to reinvent the wheel.

[David Knaack]

I have read that you can remove the internal voltage regulator to adjust the output for other purposes. Never tried it myself, but it might be interesting to investigate. 

The standard belts are pretty heavy for human power, I would consider going to a smaller belt or chain and aiming for higher rpm. 

[Kevin Fusselman]

How many things could be run on bike-power directly? All that conversion seems lossy...

[David Knaack]

I would guess 80%, maybe as high as 90% with good equipment. Maybe 90% mechanical efficiency if it is a chain?

Not bad for a demonstration system. You could probably run a standard washing machine on it if you had the battery to help during the spin cycle. 

[Stephen Beck]

I think the biggest loss is in converting back and forth between A/C and D/C power. If we were able to maintain a bicycle such that you could generate 60HZ A/C then you could directly power some small household appliances without a lot of effort, but slowing speed would be the equivalent of a brown out...I'm imagining a control system that maintains speed by shocking the rider or dangling beer in front of them when the speed gets too slow :)

[Stephen Beck]

In all reality though, the power output from each bike needs to be DC and then there needs to be an adjustment that the rider can control to adjust the amount of electric load that they are carrying to suit their individual capabilities as a rider...

[Eric Kaplan]

Well... this installation WILL be across the sidewalk from the Corona Beer Garden, but I don't think our patrons will appreciate the shocks....

I'm by no means an electrical/electronics expert, but I would assume that having the batteries would allow for the variation in power input (especially when only 1-2 people are pedaling, or when there is a whole group of 10-12).

[Stephen Beck]

What will the bikes be powering? Is the intent to use the bikes in conjunction with another power source for un-interrupted service?

[Eric Kaplan]

See below:

"The power would be captured in some form of battery system, and would be used to supplement the biodiesel generators in a specific location, such as the main concert stage. "

[Rob Townley]

i bet someone at communitybikeproject.org would be interested.  If not, they have many tools and bicycles and parts. 

[patrick]

This group of hippies might be able to help as this is exactly what they do. http://www.rockthebike.com/pedal-powered-stage/

[Eric Kaplan]

Sweet find!  I'm passing that along to our Executive Director.

Thanks!

[patrick]

I saw them in a Makerfair vid a while back. Why reinvent the wheel. When they already did.

[Patrick Joseph]

I built one last year.  I used a trainer with a dc motor mounted to it to act as a generator. 
It can be used with any size adult bicycle.  I'll bring it to the OMG some time.
I've heard that electric scooter motors can be used too.

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