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Mehul Kamdar


Some very interesting ideas - I think a modular system that combines a food processor, clothes washing drum and a battery charger would be an excellent product for many people. You could pedal away while watching television and get work done as well, while saving on electricity costs and burning calories. There's something waiting for an entrepreneur to make a success of . . .



hi Kris -
Very nice treatise on a niche subject . . i can *humbly* suggest one
more *direct - driven* arrangement at www.juicycle.com - the "
adult-height, arms-reach, multi-kitchen tool prime-mover device" -
developed in California. Although 'wheat grass' juicing is the format,
the typical hand-cranked, kitchen appliance is a low-tech,
"plain bearing" system, and usually iron-on-iron surfaces.
These bearings do not wear especially well when driven from a single
vector, like in the chain-drive illustrated on your page. . . hence
the "steel finger" drive of the type described as 'juicycle' .
. leg-powered, imitating a hand-cranking motion . . low tech
with 'clutching-and-breakaway' safety features are included . . plans available there.

Peter Silva


When discussing use of DC power to avoid losses due to added electronics needed, the article states ''there are no DC-laptops'' for example.

The opposite is true, there are no AC laptops. Invariably, there is a power brick/transformer which converts residential AC (220 or 110) into DC, between 14 and 18 VDC, depending on the laptop model. So one merely needs to now the output voltage of the power brick to determine how to feed a laptop.

Kris De Decker


@3: Thanks. Seems like a switch to a DC-network would make a lot of sense...

Kris De Decker


Lloyd Alter at Treehugger notes that the pedal-powered hydraulic log splitter (first illustration) is a silly idea more simply done by hand: http://www.northerntool.com/shop/tools/product_200316859_200316859

I leave it there since I think the illustration captures the idea of the story very well.




Drat! Peter beat me to the punch! I've never seen an AC laptop. For that matter, I've never seen an AC desktop computer. In both cases, the AC has to be converted to DC to operate the device. It seems like there aren't many devices that work better with AC power. Just about everything takes the AC and converts it back to DC for operation. I think there are some motors that are designed to run on direct AC - fans come to mind, maybe compressors. It pretty much has to be something that can run at a constant speed, since the AC current alternates at a stable 60Hz.



With todays cost of photovoltaics it makes more sense to build solar power than pedal power.
Wiring a small house with DC is possible and done sometimes like for camping or on boats. There are 12V tools or adapters for everything needed in a household.
Today AC is used because it is easy to transform. If the Voltage is doubled there is only half of the current for the same power. Thus wires can be thinner and transmission losses can be reduced. Long time was not possible to transform one DC voltage to another. So a motor generator set has to be used. With todays electronically DC/DC converters the grid could be built with DC.
On the other side a pedal powered generator could produce 230V AV directly using an asynchronous generator. the transmission and pole number of the generator would have to be set so that a convenient and efficient pedal speed can be achieved .

Kris De Decker


I don't think solar and pedal power are incompatible. On the contrary, pedal power could deliver the base load for solar (and wind), being a solution to the problem of energy storage. If you are prepared to backup your solar system with some pedalling, you will need to install less solar panels and smaller batteries.

Juliano Pappalardo


I and some friends are reading this usefull post we intend to build something, thanks from Brazil :)



Is a DC generator the best way to link up multiple pedalers or can they be combined to power one machine mechanically without the loss of electric energy transfer?

John Trask


I think that there are simpler and more energy efficient tools at least for splitting wood, namely axes, mauls, and wedges.



Splitting wood using pedal power may not be the best use of the technology BUT you don't need an _adult_ to do the pedaling. The wood splitting chores could be relegated to children/youth leaving adults free for other tasks.

Tim M


"Human power is available 24 hours per day, is not affected by changes in the weather"

Let's test this. Come down here to South Texas, first in January, and measure how much pedal power you can produce in an hour. Then, come back in August and re-perform the test. I think you'll find that the weather will have indeed affected your power output (as well as your health).

clarence hale



from a commentator over at http://thearchdruidreport.blogspot.com/2011/06/profligacies-of-scale.html came the referral to an online pdf for pedal power in work, leisure and transportation at http://www.zetatalk3.com/docs/Pedal_Power/Pedal_Power_In_Work_Leisure_And_Transportation_1977.pdf the scan is only of medium quality but sufficient for reading. some of the illustrations and pictures did not scan well.thought this would be of interest to your readers.


Kris De Decker


Clarence: thanks. I should warn readers with slow internet connections that it is a heavy download.

Tim: pedal power is better suited for cooler climates and cooler periods of the year, that is true. But the issue could be solved, for instance by moving to the basement of an existing house, or by designing buildings that are naturally cooled so that the heat stays out.

Seth: I don't know. I hope a more tech-savvy reader can answer your question.



I would LOVE to see someone incorporate a Fresnel lens to boil water then attach that motion to the pedals and viola a sun powered bike...a sun tracker could be used to get continuous power. Alas I have neither the time or resources to persue.

Tyler August


Seth: I'm no mechanic, but I suspect something equivalent to the differential gear in your car (driven backwards, pedal power to the wheels) would serve to join two slightly-off rotary sources. I'm almost certain you could rig something up; or you might find for your application a hydraulic transmission system works better; depending on what's doing you can get lower losses than electric that way. (and, again, depending what you're doing and what resources you have, it can be easier to home-brew)

After reading this post, I went looking for "Pedal Power for Work and Transportation" in the local library-- and found a wealth of 70s era 'appropriate tech' resources. Our library is awesome and I thank you for helping me realise that.



I found this posting (on a humor website) which I think illustrates your pedal power article nicely.


Kris De Decker


Full plans for a pedal powered juice maker:

Philip DeVerna


Very interesting article. I am doing a paper for school and was wondering; everything I have been reading on bicycle generators always involve a stationary bike. Does anyone know if there is a generator that one could us while using the bicycle in its normal capacity? Thanks a lot



Look at the thermodynamics: a human is a heat engine converting biomass (high quality food) to work at maybe 25% efficiency, which is then used to pedal and drive machinery or batteries.

Conversely, a steam engine can burn biomass (anything) (or take heat from solar, geothermal, or storage), at 20-33% efficiency (depending on size, bigger's usually better) to then drive machinery or make electricity.

The steam engine/power plant takes more capital, whereas humans come with society. OTOH it's a lot less picky and takes less labor.

1.2 billion pedallers -- yeah, sounds about right. Another approach is to look at power usage (10 kW for the average American, counting all domestic power use), which at 100 Watts per person is like having 100 mechanical slaves per person.



Found another great example of modern pedal power being put to good use: http://blog.makezine.com/archive/2011/12/mobile-sharpening-rig.html

ken hargesheimer


All computers, internally, operate on 12 v. They can be alternated very easily to by pass AC and operate directly on 12 v. Use a solar panel to charge the battery if necessary. free info at [email protected]

nick hein


We've built and refined a simple pedal generator that can be built entirely from salvaged materials in about 30minutes, and will provide plug-in power to any 120VAC appliance that can run on DC as well. By testing we have found that this includes TVs, lights, power tools, water pumps, vacuum cleaners, blenders. I've got a picture at this link:
A 120VDC motor from a discarded treadmill is mounted to a piece of channel that is bolted to a bike training stand, in place of the resistance unit. All that was necessary was to drill the motor mount to the channel, and the channel to mound to the stand. If you leave the flywheel on the motor you'll only get about 30V, we used a holesaw to cut the center out of the flywheel and turn it down to make a 2" dia roller which gives us about 120V when driven by a 27"/700C bike wheel. The motor can be wired directly to an outlet and regular appliances plugged in. We haven't blown or burned anything up yet, and we've tried quite a few things. The advantage of this approach is it's quick, and doesn't require any modification of the bike or the appliance that you plug in to. I built this one myself using only a drill press in 30 minutes. (A friend later made the roller with a holesaw and small lathe.)

marcos bendrao


Is it possible to generate electrical power in a sustainable and efficient way on a "mobile" bike (as opposed to a fixed one that I see on the pictures)? It's probably a very basic question but I'd really appreciate any insights you might want to share. please feel free to email me: [email protected].

Kris De Decker


Another interesting pedal powered machine using direct mechanical transmission:


Johnny Payphone


Thank you, thank you, THANK YOU for your "ditch the battery" stance! This cursed box of poison will be the undoing of the "green" movement. The inefficiency compared to a "mechanical battery" or flywheel is simply unacceptable. The disposal issues are a nightmare!

I have been developing a "human capacitor" along three paths: Flywheel, compressed air, and springs. In each case waste energy (bicycle braking) is the energy source. Anyone who has ever tried to light a light-bulb with an exercise bike knows that human energy output compared to consumption is pitiful.... when thought of only in terms of electricity!

David Mac


Just a thought, A big tank on an elevated platform, a little hydraulic ingenuity and all these machines will work (Water motors are well researched) a pedal powered pump (and a windmill) to fill the tank. Pedal when you want, use the energy when you want. Very low loss systems. Not a new idea, just a little forgotten.



Hey People!

Listen, coming from someone who knows a LOT about motors: If you wish to generate electricity with your pedal-powered prime mover, then DO consider that ugly, HEAVY, bulletproof, 10+HP AC compressor motor that the out-of-business company down the road abandoned as your generator..

You can Quite easily rectify its output into DC with the use of suitable diodes. This also means that by monitoring a voltmeter whilst you pedal, you can pretty much CHOOSE the voltage that you want (12 / 24 / 36VDC) without driving the motor to its nameplate speed.

Industrial diodes do have a larger voltage drop, but you can easily find them used and in ample supply.

It is actually common in the electrical / engineering trade to rectify 347/600VAC power supplies with these semiconductors -- and we DO.

Good on us -- stick a PLUG in their dirty oil pipe.



Question... I am working on a project that includes a bike with a grain milling attachment on it (actually used for grinding coffee). Also, I would like for the bike to be able to heat water, fairly efficiently if possible. Does anyone have any relevant ideas or links to contribute? It could use mechanical energy but I am also considering other "sustainable" options. Thanks!



What are your thoughts about a Pedal Powered PTO? A video and website with more information.


Seems it can just run anything with a shaft. Something new for this day and era?

Jerry Friedman


Many of the comments about bicycling were false. While aerodynamics are critical to bike speed the seat tube angle is critical to generating power with your legs. If you sit further back from the crank center you can't 'spin' the pedals very fast which limits the HP and increases the torque. Conversely most racing bikes have steeper angles which allow less pressure to be applied to pedals spinning much faster.
If you push very hard at a slow rate your legs will go into 'oxygen debt' and become useless quite soon - 'Spinning' at a rate of 92 beats per second allows your cardiovascular system to come into play and sustain much, much longer periods of work. Sitting back too far and pushing too hard will cause harm to your knees as well.
Bicyclists learn to 'spin' in a circular motion which brings more muscles into the game.
Flywheel systems and water transfer energy systems employ sustained small efforts to develop usable large forces - So correctly designing the 'user interface' would make the difference between a workable system and a novelty (that has potential heath risks).
Many of the designs shown (seats of plastic milk crates?) don't look practical at all from a peddler's perspective.
Many seem to put the peddler at a mechanical disadvantage even as he sits on the thing...

tom foxe


While much of the comment is factual, these criticisms of pedal-powered generation are too negative for me. They fail to recognise that pedal-power generation releases us from the tyranny of centralisation. Activities such as music concerts and cinemas don't have to depend on the national grid and commercial cinema chains,and they can be done cheaply so the admission price is low.
OK, it IS more efficient to operate machines wihtout electricity if it can be done, but this doesn't mean that bicycle-powered generation isn't worthwhile.
It would have been educational to show the BEST examples of pedal-powered generation, with a headline like "How to get the most out of pedal-powered generation"
Please encourage good work, don't trash it.

Katherine P


Thank you very much for this article, which has moved my ideas on radically from "I wish I could power my PC with cycling while sitting at it".

I totally support Mehul Kamdar's comment right at the top. The spin cycle on a washing machine is crying out for a connection to flywheel-stored energy, eg as generated by Job Ebenezer's dual-purpose bike (which I think answers Marcos Bendrao's comment 25) - I love the flipped carrier/stand too, btw.

And there's lots of idle time in front of the TV or computer (we'd need new, higher & deeper, desks for the latter, of course) to generate it. Plus plenty of recent research on how damaging all that sitting around is for our health.

Come on, entrepreneurs, please build it!



This was really helpful. Having decided to acquire an exercise bike (for fitness) I was really into the idea of using my energy to power something. Since I don't use mechanical tools (and I don't make smoothies) I would have gone for the rather pointless battery stuff - and I'd never have been able to generate the embedded energy in the kit. I am hopeless at DIY and not very fit so now I'll just concentrate on the health benefits (and reducing my energy use). Dee

Ron Shook


Articles such as this tend to get my imagination juices flowing. While reading the comments I started thinking along the same lines as the commentor, David Mac, "A big tank on an elevated platform, a little hydraulic ingenuity and all these machines will work (Water motors are well researched) a pedal powered pump (and a windmill) to fill the tank. Pedal when you want, use the energy when you want.

My thoughts were even simpler. About a year or so ago there was an article about an invention for afterhours reading or work light for the developing world which was dirt simple, no battery, just a tiny mechanical generator and an LED bulb. It was powered by gravity. You simply hung it up, filled a bag with 20 lbs of rock or dirt, lifted the bag a couple of feet and had light for half an hour with each lift of the bag. They figured the cost for this device in scale quantity would be about $7. This sure seems like a lot simpler solution than the Nepalese example in this article or storing water up high for an electricity generating water turbine.

It sure seems like a scaled up version of this tech using a bike hooked to a block and tackle lifting a 500 lb to one ton weight up 5 or 6 feet would be a way to store and supply considerably more power for small electric or mechanical powered in-home industry.

Transfer this to the developed world and a multi-position exersize machine (think Bowflex), not just pedaling, could do the same thing. For example, exersize for half an hour and you've got enough energy stored to watch 2 hours of TV or whatever. Make use of Michael Pollen's food and eating principle that you can eat as much junk and deep fried food as you want as long as you make it yourself and have to deal with the hassle and mess. In this case it's watch as much TV as you want as long as you make the power to do it yourself.

Kris De Decker


@ Ron:

Great idea. I think you are referring to this "gravity-powered" system:

braden godden


haven't we already got potential human power plants? why can't our existing gyms be converted so that, not only pedal power, but all the other activities like running, leg pulls & pushes, arm and rowing excercises all used to manufacture combined power to be added to the grid, every town , every city... excercise with a free power bonus! if its too difficiult to convert exising gyms... create new ones with incentives for super generators... just an idea bg



Found this website looking for kinetic sculpture ideas. I like the idea of gyms as a energy resource and would suggest taking it a little further having our countries jails setup this way. There seems to be a lot of human power there, that is not being put to good use.



great article, and thanks to the author. reminds me of the Professor on Gilligan's Island! tell Michelle Obama that the fight against obesity in America's kids can be solved here: if kids want to watch TV, use the internet, or play video games for an hour, they have to pedal a stationary bike for 30 minutes.
thanks for the inspiration. i hope i can create something out of the suggestions here.

Greg Marlow


Peddle power is still a carbon based energy source. The carbohydrates and fats you eat are used to make the energy for your muscles and you finally exhale carbon dioxide gas.

Mario Juarez


La colección, de experiencias es muy buena, y en Maya Pedal estamos fecilices de proveer, bicimaquinasa personas, con interes en nuestra alternativa, dandoles soluciones viables, como independencia energetica, a su salud, y productividad.
sinceremente. Mario Juarez director Maya Pedal, www.mayapedal.org, https://www.facebook.com/MayaPedal

David Remus


A juicer, for example, is very high tech. Why not simply eat the vegetables and fruits, eliminating the need to expend energy building yet another truly useless machine? The best low tech idea often is to simply do as people did before electricity.

Imagine the extra water and energy needed to grow more food, ship it to the pedlaers, and feed people spending a lot of time exerting themselves to run machines we don't really need. And yes, an army of slaves generating useful work pedaling makes it easier on the person not mindlessly pedaling. Slave owners knew that thousands of years ago.



@ (30) Amasa
To heat water by peddling power a heat pump with the peddling putting the condenser into the water tank. In hot climates a suit of tubes full of cold water can keep you cool and preheat the water for the boiler.



All you need to do is hook your generating cycle into the grid. You will produce direct power that can be traded for power to your own home. This removes the battery issues. Most of the research was based on using a traditional bicycle to generate electricity. Manoj Bhargava with Free Electric/Billions in Change is marketing a bycycle designed to create electricity. By gearing the pedals to a weighted flywheel they have increased the electricity generation capability beyond that of a traditional bicycle. It's easy to poke holes in failed attempts. We need to start thinking in terms of solutions and quit all the naysaying.

Oscar Nitz


If we could get our society to the point of energy efficiency where having shifts of people pedalling bikes is a viable alternative for power production then we may as well go back to using fossil fuels because we would use so little and it would become viable.

Byron Hale


There are DC laptops. Dell Computer has AC adapters, but they supply DC to the laptop.

Here, along the Cascadia Fault (effectively from California's Golden Gate to Canada, or maybe Alaska, we will be needing low-tech solutions.

Formally from Cape Mendocino, heading North, the power grid is expected to be knocked out from San Francisco to Sacramento and West of Highway I5, stretching at least to Canada. The catch is that we don't know when. The last time the fault blew was 1701, as evidenced by tsunami devastation in the State of Oregon and in Japan.

When this happens, we can expect no power to pump gasoline.

Keep the articles coming.

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