Pedal-powered Generator-- (its day has come) : LUSENET : TimeBomb 2000 (Y2000) : One Thread

A friend sent me a link to a web page written by a guy who built himself a pedal-powered generator. He writes,

"Burst output: 25 amps at 17 volts (425 Watts). 30 minute average output (back when I was in shape) 150 Watts. \snip\ For immediate electrical use, cigarette lighter outlets provided ready access to the juice. I even had a small 12v toaster oven, and pedaled my bagels to toast more than once. For storage I would charge a 12v 100Ah fork-lift battery. I could approximate the output of a 10 amp battery charger."

Read the whole story here" href=>Pedal Powered Generator.

Wonder if anyone has working drawings, parts list, and controller schematics already worked out? Or same could be worked up by someone with the right skills.

I figure there'd be a real market for something like this now, either assembled, in kit form, or just the drawings. A rig like this would be a lot quieter than an IC engine, wouldn't need stored fuel (not counting food, which is there by default!) (Plus you get to keep fit while holed up in the bunker... or wherever you plan to be.)


-- Tom Carey (, November 06, 1998


You might try robbing the alternator and the voltage regulater out of your car and rig your bicylce to turn it to produce the same 12volts your car does and charge batteries. I also have a 12DC to AC convertor I bought from Wal-Mart that works with a cigarette lighter. It is good for up to 50 watts.

-- James Chancellor (, November 06, 1998.

Of course, what you'll be doing is fueling a generator with the rice and beans you've stored - a very inefficient use of food!

-- Ned (, November 06, 1998.

Swiping the alternator and voltage regulator out of a car sounds possible in pre-computer-chip cars, but what about modern vehicles? Aren't the voltage regulators part of the car's computerized ignition system? What sort of controllers or rpm indicators do you need? I know this has been done before -- I've seen photos in homesteadmags -- but are is the information readily available somewhere?

So many questions, so little time for answers.

-- Out of shape (get@sweaty.pedals), November 06, 1998.

"... inefficient use of food!"

Reckon it is. But food will be there -- if not a generator wouldn't matter anyway. Can't promise that for gasoline or diesel fuel . And as others have noted, an internal combustion engine running makes a good deal of noise. In some scenarios this may be inadvisable.

-- Tom Carey (, November 06, 1998.


I'm always fascinated by the innovative things people come up with to keep their old lives operational. I also love to see creativity challenged. Makes me think we just might make it through Y2K somewhat damaged but with the spirit intact. Personally, though it's not for everyone, I prefer to camp, wake up with the sunrise, sleep when it's dark. My preference is to keep things simple, as someone said in an earlier post.


-- Diane J. Squire (, November 06, 1998.

Hi Diane --

Maybe a tad of projection in your "innovative things people come up with to keep their old lives operational." But your point's taken. There'll be amazing ingenuity demonstrated.


1) My wife and I live in an apartment building surrounded by trees. No place to put a solar panel. With a rig like this, properly configured, even I could keep a radio going. It might be nice to have an all-band radio receiver -- not to be clueless as to what's going on outside. In some situations, showing a light might not be a good plan. In others, it might not be a problem. What's to do those long dark winter nights? With a little light, Scrabble, Monopoly... or read Gibbon, Spengler, Tolkien...whatever. We're not figuring to run a fridge and microwave!

2) Fact remains that anyone with a viable design like this right now could probably improve his cash supply -- bolster resources -- defray preparation expenses-- pay off debts-- live it up-- whatever.

-- Tom Carey (, November 06, 1998.


There are lots of ways to do that. I prefer teaching camping 101 (and I also prefer hot showers) because it's the simplest thing you can count on, for everyone, no matter where they are. Hurricane Mitch has illustrated, illuminated, that one for us all. Not every one out there is a MacGiver (spelling). Keep it simple...kiss, kiss.


-- Diane J. Squire (, November 06, 1998.

Just a comment on the efficiency of food as fuel.

Some time ago I got into an argument with my brother over the question of excercise versus diet in weight control. The following was uncovered during that debate:

One calorie (in chemistry or physics) is defined as that amount of heat energy required to raise the temperature of one gram (1cc) of water, one degree centigrade.

One calorie (on a food label in the USA) is equal to one thousand of the first kind.

In order to burn one calorie (the chemistry kind), the human body must perform approximately 3000 foot pounds of work; that is, it must move one pound one foot against the force of one gravity, three thousand times or move three thousand pounds the same way once.

The internal mechanism that regulates body temperature burns, on the average, about 1500 of those calories in each 24 hour period. If the temperature is significantly higher or lower than what that body is accustomed to, the energy consumption will increase.

I'm not sure just how many calories we could get out of a gram of gasoline or diesel fuel, or how much work our machines could do with whatever we got, but I'll put my money on the beans.

And, that doesn't even take into account the possibility of subsequent methane generation! (although collection could be something of a problem)

-- Hardliner (, November 06, 1998.

I don't even want to see the PLANS for that methane collector. BTW try your local junk yard for old alternators. Also, methinks that a boating store could help with finding a new one without chips, as marine motors are low tech compared to autos.

-- Uncle Deedah (, November 06, 1998.

Uncle, a friend was mentioning that they thought sail/power boats had something that was able to convert sea water into something drinkable. Does anyone know something about this?


-- Diane J. Squire (, November 06, 1998.

Ms. Diane, Please check through the older threads - this was brought up before, but I didn't keep a copy (or mark it) so I'm not sure which specific one is relevent.

-- Robert A. Cook, P.E. (Kennesaw, GA) (, November 06, 1998.


If one 'chemistry' calorie has enough energy to allow a person to lift 3000 pounds one foot;

And there are 1000 chemistry calories in a food calorie;

Since there are about 1700 food calories in a pound of rice, one pound of rice has enough energy to lift 3000 pounds (a ton and a half) 1,700,000 feet or over 300 miles!

Does not compute!

-- Ned (, November 06, 1998.


A calorie is heat energy. The number of calories in a particular item of food is determined by burning (actually combining with oxygen inside a controlled environment and measuring the rise in the temperature of the water jacket) the food item in question.

The human body is not only incredibly efficient, it is far more sophisticated than a calorimeter (the device with the water jacket) and metabolizes the food in a much more complex way.

If you consider the energy contained in the molecular bonds in the food (which is released as the food is digested), you'll easily see that there is indeed enough energy in a pound of rice to do as you say and then some!

-- Hardliner (, November 06, 1998.

The human body burns rice into carbon dioxide and water, just like a fire. In turning rice to heat, the body is equally efficient. In turning it to mechanical energy, it is considerably less efficient. If you were correct, I would be routinely breaking the sound barrier on my bicycle.

- Ned Taylor B.A. (Physics) M.D.

-- Ned (, November 06, 1998.


Desalinator=$$$$$$$ Needs juice to run=more$$$$$

$64,000 answer is: Solar distiller instead.

-- Uncle Deedah (, November 07, 1998.


I am on record in this forum as calling for, "Standin' up, 'fessin up and payin' up", when in error. I stand by that.

As for the "'fessin up" part, I'm also on record as adhering to the standard of accuracy. I've got to tell you that the 3000 ft lbs/cal figure is my brother's (BS in Chemistry and a Dental Surgeon on the faculty of a dental school). I took it at face value and it's been stashed in my mind as an acurate value for a number of years now, but if it's incorrect, I want to know about it so that I can replace it with a correct figure or, at least, mark it as incorrect and remove it.

And, since I'm the one who shot his mouth off here, if it turns out to be wrong, I'm the one who'll do the "payin' up".

I do however have some problems reconciling your last post with my understanding of how the body metabolizes food.

It seems a real good bet that my knowledge of bodily chemistry is inferior to your own and probably much outdated by comparison as well. If you would be so good as to hear me out and correct my information where appropriate, I would sincerely appreciate it, and I suspect that the other readers of this thread would find it of value as well. (If not, they can obviously choose to disregard all of this)

Your response has caused me to dig for old class notes and textbooks (notably, Organic Chemistry, Morrison and Boyd, 3rd Ed., Copyright, Allyn and Bacon, Inc., 1973 and Biology, Helena Curtis, Copyright, Worth Publishers, Inc., 1968.

Your statement that, "The human body burns rice into carbon dioxide and water, just like a fire", is something of an over simplification of the processes involved, as you must know. Organic Chemistry says, "Instead of a single reaction with a long plunge from the energy levels of carbohydrates and oxygen to that of carbon dioxide and water--as in the burning of a log, say--there are long series of chemical reactions in which energy level descends in gentle cascades." (p.1170)

My understanding is that the reactions collectively known as the Krebs cycle (I remembered the name, but almost none of the details), are a great deal more efficient than the internal combustion machines that man produces. Biology confirms this when it says, "In this way, an estimated 60 per cent of the energy of the glucose molecule ends up recovered or conserved in the form of useful energy available to the cell for work, with only 40 per cent lost as heat and entropy in the process. In a gasoline engine, only 25 per cent of the energy liberated during the combustion of the fuel is converted into work." (p.149)

Biology reinforces the concept of greater efficiency further when it says, ". . .cells have developed methods for harnessing energy which act with a precision and an efficiency far exceeding that of any man-made machine. Cells, moreover, are specialists in energy transformations; they cannot use heat energy or mechanical energy or electrical energy. Almost all of their energy exchanges involve chemical energy because this is the only form that can do work in the watery environment of the cell." (p.140)

Another thing that I remembered, but of which the details eluded me, was that the muscles performed some sort of a "trick" when the reactions didn't happen rapidly enough. "Organic" refreshed my memory as to the "trick" with, "Ordinarily, the energy needs of working muscles are met by respiration. But, during short periods of vigorous exercise, the blood cannot supply oxygen enough for respiration to carry the entire load; when this happens, glycolysis is called upon to supply the energy difference. The end-product of glycolysis, lactic acid, collects in the muscle, and the muscle feels tired. The lactic acid is removed by the blood and rebuilt into glycogen, which is ready for glycolysis again." (p.1172)

Again going to Biology, I found, "As you can see, the breakdown of glucose is accomplished by a series of separate steps,. . . The chemical modification that occurs at each step is very small: The molecule literally falls apart, a little at a time. The whole point of glycolysis is to release the energy of glucose in small, separate steps. If the energy of the molecule were liberated all at once, it would produce heat. A sudden burst of heat would be of little use to the cell and could be destructive. By releasing the energy in a series of small steps, the cell loses only a little of it as heat and is able to conserve or recover a sizable proportion in the form of useful chemical energy." (p.143)

Now, in as much as I'm far more of a technology type than a biology type, and having learned my chemistry from books which made statements such as, "Its action is by no means as well understood as. . .", and, ". . .but let us look at the kind of thing that is believed to happen" (Organic, p.1174), I find myself here in somewhat the same position as the ignorant savage confronted by superior technology who believes that he is witnessing magic.

I have what I think to be a working understanding of the principles of conservation of energy and I know that Nature never provides something for nothing, but I had supposed that the postulated superior efficiency of the biological mechanism was of an order of magnitude or more and that the body was simply capable of making far better use of a calorie than your reply indicates. There have been times in my life when I have sliced off a bit of plastic explosive (C4) as you would a pat of butter and lit it with a match to heat my c-rations. I know that I "wasted" a lot of energy by merely burning it, but it served the purpose at the time. I've always viewed the calorimeter and the body as analogous to the c-rations and an explosion (in terms of energy usage).

As for the sound barrier, those machines of my experience which break it, do so by burning a great deal of fuel in a very, very short period of time. If they were to consume the same amount of fuel, but at a fractional rate, they certainly wouldn't achieve Mach flight. I had supposed that, "By releasing the energy in a series of small steps. . .", such would be precluded on a bicycle propelled by a man.

Is it possible that I got the type of calorie confused in my memory? That is, would my (really bro's, but mine now) numbers "work" if based on a single "food" vice a "chemical" calorie?

Well, here I stand in cyberspace with, it appears, egg on my face and I shall be glad to get it removed, one way or another. I have been blessed (or cursed, I'm never quite sure which) with the affliction of curiousity since birth and this is not the first time I've dealt with broken eggs. In the end though, I expect to be better for the exchange and hopefully less of the ignorant savage witnessing "magic".

Ned, I expect that you're a busy man, so if you can find time to afford me some relief here, I will be greatly in your debt.

-- Hardliner (, November 07, 1998.


A human's daily basal caloric requirement is about 1500 KCal daily, or 1,500,000 'chemistry' calories.

What you say about the way the body metabolizes glucose via the Krebs cycle is correct. However, in a fire we have carbohydrate in, CO2 and water out. Same result in the Krebs cycle, via many small steps. Conservation of energy demands that the total amount of energy released is the same. In the Krebs cycle some of the energy comes off as heat, and some as ATP, which is the fuel that cells, including muscles, run on. I don't know offhand the efficiency of the ATP to mechanical energy reaction but of course it's considerably less than 100%. We have losses in carbohydrates to ATP, and more losses in ATP to mechanical energy.

One calorie is 4.2 joules. A joule is the energy needed to accelerate one kilogram by one meter per second. The acceleration due to gravity is 9.8 meters per second. Therefore, to raise one kilogram by one meter requires 9.8 joules or about 2 calories. 1,700,000 calories will raise a ton and a half (~1500 KG) 430 meters - considerably less than the 300 miles your figures give - and that's at 100% efficiency, which cannot be achieved.

The 'trick' you mention, anaerobic metabolism of glucose, is a way for a cell to run up an oxygen debt. The lactic acid produced has to be metabolized aerobically eventually, and the eventual energy result is the same.

BTW, I appreciate your not having replied with a string of invective - not that it's your style, but it is something that I've had to grow used to.

-- Ned (, November 07, 1998.

Do a search for VITA. It's the Vol in Tech Assitance. They do all sorts of low-tech solutions for developing countries and have all sorts of publications and I think some of them are along the 'manual' generator idea.

We need to remember that most of what we're trying to do has already been done in the past 20-30 years by people trying to bring 'civilization' to developing countries. We just have to dig it out and apply it as we need it. Ever seen pictures of some of the rivers in India? They have all these little floating platforms with a 12v alternator attached to a paddle-wheel. Wires going everywhere since everybody has their own generator for themselves. Pretty neat...

-- jd (, November 07, 1998.

Second part of the equation you need to include is that the change in chemical energy is all that can be used - the 25% efficiency of a gas engine is including that factor by measuring the exhaust energy of the waster gases and their temperature/pressure.

Chemically, you must include the potential chemical and heat energy of the by-products of life (sewage and CO2 and raised heat of the body, sweat, chemical and thermodynamic energy in the water exhaled, etc.) to get the working comparison of a body to a gas or steam engine in the "energy balance" you're looking for.

Max efficiency of a large steam plant is is 42 - 45% - and a lot of utilities spend big dollars looking for a 1 or .5% increase in that. Yes, it's not the efficiency of the mechanical/electrical world that has so much impact - its the amount of energy that can be applied for so long that is important. No person could turn even a simple fan motor like those in your house HVAC system all day, all night, at the same speed.

-- Robert A. Cook, P.E. (Kennesaw, GA) (, November 07, 1998.

Well, Ned, thank you for your gracious assistance with my "egg problem". Once again, my hat fits properly and I not only feel less the ignorant savage, I'll have a much more cautious approach to any future "facts" from my brother!

I also have a clearer than ever understanding of the capability of the human body. After my initial pair of "fox's paws", I started digging so that I'd not end up wearing my entire breakfast. In the process, I learned more than I ever wanted to know about ATP, ADP, NADred and acetyl-CoA. It was only your reply, however, that gave me a clear view of the relationship of food consumed to work capability.

Robert, I appreciate your contribution to the answer as well. I learned more than a few things from it. As to your final statement, here is a partial posting from the hydro-dam operator that I've quoted before, that illustrates your point, I think, rather well.


Date: July 06, 1998 05:37 PM Author: Lane Dexter ( Subject: You Said It, Mud

For years, we have had a bicycle generator for the tourists. It's a conversion of an exercise bike to drive a car alternator. As voltage comes up, it cuts in additional light bulbs. It starts out with a couple 25 watt bulbs, then a couple 50 watt bulbs, then a couple 100's. Get on and start peddling; as you rev up, you feel the additional resistance as the bulbs kick in. To light up all six (350 watts), you really have to WORK. Just sustaining the first 50 watts worth will tire you before too long.

The BayGen radio and flashlight are examples of human powered generation, but they are quite small. Mud is right; though you may build a more efficient "gen-cycle" than ours, you won't sustain much more than 100 watts, and keeping that up will be work.


[Hardliner again]

When all is said and done here, I guess I'll still vote for the beans and rice (I hate the taste of gasoline), and plan on using the thing to charge batteries when I'm in a particularly masochistic mood. For Uncle D, I PROMISE not to even consider a methane collector and to locate said device in a NO SMOKING area!

-- Hardliner (, November 08, 1998.

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