Skip to comments.Pedal Powered [Electric] Generator (Energy of future?)
Posted on 07/25/2007 1:17:54 PM PDT by topher
Preface by FreeRepublic TOPHER
With the development by FireFlyEnergy of a new technology for batteries, how to recharge batteries becomes a problem. Here is a way that does not use oil, gasoline, coal, etc.
If a one billion people on the planet would pedal 20 hours a week, the savings would be??? (end teaser)
I built the first version of the Pedal Generator in 1976. Let me describe my invention to you. As an improvement over similar bicycle generator designs, I went all-out for efficiency and versatility. While a bike generator is an alternative to my design, pedaling will be uncomfortable and inefficient, and powering non-electric equipment may be difficult. A key feature in my design was a 36" particle board disk with a groove routed in the edge that served as the flywheel and crankshaft for the permanent magnet 36 volt DC motor ( 1 2 ) seen at the upper right edge of the device. A small-pitch chain provided the power transfer system. The groove around the outer edge was lined with "rim strips" - thin rubber straps that prevented the chain from slipping and digging into the particle board. They are standard bicycle parts. The motor was obtained around 1985 from Northern Hydraulic, now known as Northern Tool and Equipment Company. It is a General Electric Permanent Magnet Motor, model 5BPA34NAA44, a very nice heavy-duty, ball bearing unit. I paid USD $29 for it if I remember correctly, and I still have it.
The bottom frame of the Pedal Generator was welded steel plate and channel, the crankset was an American Schwinn ball bearing set, a cotterless crank conversion spindle, alloy cranks and cheap pedals with toe clips.
The crankset had a steel chainwheel on it. I drilled some larger holes in the chainwheel and bolted the particle board disk to it. It was strong enough (fine Schwinn steel!) to hold the weight of the particle board disk and run true. I routed an oblong hole through the particle board disk for the "arm" of the crankset.
The seatpost and handlebar tube were standard galvanized water pipe. The generator/motor was mounted on a piece of 3/4 plywood visible in the motor pictures seen above, which was then bolted to the water-pipe frame.
The particle board disk was a key feature of this unit. The weight of the disk served as an excellent flywheel. Human legs and pedals create an extremely "peaky" torque curve, resulting in jerky motion and lots of stress on parts. The flywheel smoothes this all out by absorbing part of the energy on the power stroke, lowering peak torque, and releasing it on the "dead" part of the stroke, creating torque where Human legs/pedals cannot generate any. Another thing to remember is that Human legs do not like extreme stress. The flywheel allows the Human to avoid having to generate extreme pressure during the power stroke just to make it past the "dead" spots. Many "bicycle converters" lack the flywheel characteristic because tires/rims are designed to be so light.
Noisy but extremely efficient, I have powered 12v CHAIN SAWS directly (yes, while someone else cut wood with them) with this unit.(1) Pedaling position was similar to a bicycle. The seat is barely visible at the upper left of the photo, and the handlebars (dropped, as on a ten speed road bike) are at the upper right.
Burst output: 25 amps at 17 volts (425 Watts) at 25 years old, and 265 Watts at 52 years old.
30 minute average output (back when I was in shape) 150 Watts
A drill chuck threaded into the end of the motor shaft provided power for a flexible shaft drive. Drilling 1/2" holes through 2x4 fir with this arrangement was easy. The flex-shaft was rated at 1/2 HP (a commercial unit, about 3/4 in. thick - not a "dremel" type!!) and I was still worried that the torque would be too much for it.
For immediate electrical use, cigarette lighter outlets provided direct access to the generator output. I even had a small 12v toaster oven, and pedaled bread to toast more than once. For electricity storage I would charge a 12v 100Ah fork-lift battery. I could approximate the output of a 10 amp battery charger.
Instrumentation consisted of a voltmeter and an ammeter, which together provided me with state of battery charge, output watts and somewhat of a "speedometer." The math needed to determine power output was easy: VOLTS x AMPS = WATTS. A 50 amp silicon stud diode mounted to a four inch square piece of aluminum sheet metal prevented reverse current flows (which would cause the motor to turn the flywheel, instead of the other way around!), and became satisfyingly warm after long sprints. It was mounted in the center of the aluminum plate visible in the first motor picture. For top efficiency (and safety), a switch was also installed to completely isolate the diode and motor/generator from the battery.
I had to be careful - I burned out several expensive 12v halogen bulbs powering them directly. If there was no voltage control, exuberant pedaling would fry the bulbs in short order. When the storage battery was connected, this was less of a problem because the battery tended to even out the voltage, but sprinting would still raise the voltage to the danger level.
I experimented with various non-electrical devices, connected directly to the chain with their own sprockets. I substituted a ball-bearing 3600 GPH Labawco type P pump for the generator, resulting in amazing water pumping capacity. The suction from the pump was strong enough to collapse the heavy wall 1 inch vinyl tubing used for the intake (radiator hose would have been better, with the wire reinforcement) and the output shot a stream of water about 25 feet across the street. A 5 gallon bucket was emptied using this pump in less than half the time it took a garden hose to fill it. I believe the pump was driven to capacity (1 gallon per second, emptying the bucket in five seconds) in sprints.
I also tried smaller pumps, including a MATEX rotary vane pump, with great success. I have had difficulty locating that brand recently (30 years later!), but Northern Tool & Equipment carries a pump that appears to be identical. And what a great price!
I never had a chance to determine how efficient the Pedal Generator was in converting mechanical energy to electrical energy, but I believe it was probably quite good. When it was running, only 4 ball bearings were turning, the only high-speed part was the armature of the motor, and I know from research that chains can be as high as 97% efficient in power transfer. The permag motor was probably better then average at power generation, because it was designed to be efficient as a motor. In "reverse" tests, with the motor driving the unit with no load, the power consumed was less than an amp at 12 volts. This is negligible, and much of it was resistance loss in the motor windings, since the motor drew half an amp with no load connected to it.
Status: The Original Pedal Generator never broke down, and never wore out. I still have the motor and flex-shaft, but several job-related moves finally forced me to dismantle the unit, even though it was still in perfect working condition.
(1) Three things about the MINIBRUTE 12 Volt DC chain saw. One, I was in great shape and probably was generating over one horsepower in the sprint. Two, the branch/log was about three inches in diameter - not anything near the 10 inch bar length. And three, the saw was a 12 volt saw, so it was designed to be efficient. The literature from the saw said that the motor was a permanent magnet Bosch electric winch motor, which was a good match for the maximum output of the Pedal Generator. It was great to see the chips fly!
There are many other possibilities that I can think of for this device. The efficiency and variable speed of the output are two features that can be exploited. Since it requires no fuel, and is not affected by time-of-day or weather, it would make an excellent Human-powered emergency generator, ready for any blackout. Here are some other devices that could be powered by the basic unit:
Basically, any device that was hand cranked, foot-powered, or powered by a fractional horsepower electric motor could potentially be converted to pedal power.
Also note, if the base unit is being used to power an auxiliary device in addition to producing electricity, adding a solar panel will result in additional power from the motor/generator! That means whatever device you are powering would receive the combined power of the Human pedaler and the solar panel. This combination makes the best of both power sources, as efficiency would be very high, because the solar output would not suffer the losses of being stored and then extracted from a battery. Charging a battery and then extracting the same power is less than 80% efficient, and can be much worse. Direct utilization captures that wasted power.
Finally, keep in mind that a tandem setup for the pedals, with the pedals out-of-phase, doubles the power and smoothes out the power flow. Only one "flywheel" is needed, so this enhancement needs only a simple pedal/seat addition to the basic unit. With out-of-phase pedals, peak torque is not increased, so other parts of the system are not stressed. The torque curve for a complete revolution of the flywheel simply smoothes out, while RPMs stay constant, resulting in twice the power.
News: Tue May 8 23:09:04 PDT 2007
So far in 2007, the PPPM has been on display at the Burning Man Green House event, Earth Day, and Springtime in Guadalupe Gardens. Record power was produced at Guadalupe Gardens: 147 Watt-hours! See the PPPM Live!
News: Sun Dec 10 14:29:39 PST 2006
PPPM designs and technology powered The Boycott Coca Cola Experience in London.
News: Wed Oct 18 22:20:18 PDT 2006
The PPPM will power the Wasteland installation at the Bates Museum by Artist Virginia Valdes.
News: Sun Oct 8 10:30:00 PDT 2006
The PPPM was the power source for a Demonstration of Incandescent vs. Compact Florescent light bulb energy use at an Energy Fair
News: Sun Sep 24 16:55:16 PDT 2006
Today I tested a 1.5 Farad Xpress Digital Power Capacitor, also known as an Audio Stiffening Capacitor, as both the power "smoother" and the voltmeter for the PPPM. The test was a complete success. I ran two different devices directly from the PPPM. One was an IBM ThinkPad T40 Laptop, and the other was a 12 volt air compressor.
The capacitor provided a real-time voltage display, and it stabilized the voltage and amperage being produced by the PPPM. When passd through a Targus 12 Volt DC converter to the laptop, pedaling was smooth and easy. With a comfortable seat the laptop could be pedaled indefinitely. The air compressor required more effort, especially when it was used to pump the tires on my eGO Electric Vehicle to 100 PSI.
The capacitor was on sale at Frys Electronics for $19.95 - a great deal considering it is both a capacitor AND a voltmeter. While it does not provide as much information as the Watt's Up I describe below, it does address two critical needs: voltage measurement and power stabilization. It's not in the same league as my Maxwell 58 Farad capacitor, but it costs 7 times less! It's perfect for a basic PPPM.
News: Wed Aug 16 20:30:33 PDT 2006
The Pedal Powered Prime Mover is a hit in Australia! - Main BioSUB Site
News: July 31, 2006, It has been one full year since I brought the Pedal Generator back to life. I have been riding that generator every day, and storing the power it produces in a battery bank. Motivated people from all over the world have bought plans to fulfill their own visions for Human Power. It's a success!
Previous News: On July 31, 2005, I rebuilt the Pedal Generator, and I call the improved model the Pedal Powered Prime Mover, because it can do much more than generate electricity.
I built the Pedal Powered Prime Mover (base, frame and flywheel) in one day!
The design is similar to the early version in the picture at the top of this page, but I made a point of reproducing it in a way that would be friendly to a "do it yourselfer." The only tools I have used are: screwdriver, hacksaw, wrench, hand drill, and wood chisel. I finishd it with only those tools, and all "off the shelf" parts. It's great to have the Pedal Generator back online, as the new and improved PPPM I.
I recently installed a power measuring device called the "Watt's Up" from BatterySpace.com. (search for "battery analyzer") I think it is the best such device I have seen for this use. Disclaimer: I was so impressed with this device, I joined their affiliate program, and the link above goes to it. If you prefer to go directly to a different site, PowerWerx.com, visit http://www.powerwerx.com/. This device provides a real-time display of volts, amps, watts, and other valuable and intersting information, such as peak output! It has become the "speedometer" and "odometer" for the Pedal Generator. Here it is in action! It's small, powered by the electricity it is measuring, and it measures in real time. In this display I am pedaling with no hands to take the picture, and the display shows an instantaneous output of 2.68 Amps, 15.83 Volts DC, 42.4 Watts, and also shows that the peak output for that session was 51 Watts. The display cycles through other useful information, like total Watt-Hours and Amp-Hours produced in that session. It sure beats the old panel meters I had on the original Pedal Generator!
Here are some movies of the PPPM I in action. One of the last issues I solved was a slight alignment problem with the flywheel. If you listen to the movies, that is the loudest sound. The final version of the PPPM I - which is used in the Ultimate Pedal Powered TV Movie - is MUCH quieter.
Some of the devices shown in the movies are powered by 110v AC through an inverter, some are powered from 12 volts DC directly from the PPPM I, and some are powered mechanically. No batteries are used in ANY of the movies!
Ultimate Pedal Powered Television: PPPM I, 400 Watt Victor 12v DC to 110v AC inverter
· 14 Inch Television: Short Movie, Long Movie, 12v DC 1 Farad capacitor
(Note: the black bar on the TV screen is caused by unsynchronized camera and TV frame rates. The picture is actually perfect.)
· 32 Inch Television 12v DC 58 Farad capacitor
Pedaling Effort: Light to Extreme, depending on the screen size ;-)
Pedal Powered Laptop Computer: PPPM I, AD-SDR-70W - Universal DC-DC Regulated Adapter, 12v DC 58 Farad capacitor
Pedaling Effort: Light to Medium
Pedal Powered Water Pump: PPPM I, direct drive to 3600 GPH Labawco type P ball-bearing pump, 6 gallons pumped during the movie
Pedaling Effort: Medium
Pedal Powered Fan: PPPM I, 400 Watt Victor 12v DC to 110v AC inverter, 12v DC 100,000 MFD capacitor, Box Fan
Pedaling Effort: Moderate (Low Speed), Medium (Medium Speed), High (High Speed)
Pedal Powered Air Compressor: PPPM I, directly powering 12v DC air compressor, 15 PSI added during the movie (50->65 PSI)
Pedaling Effort: A good workout. 100 revolutions generated 30 PSI. Easier than a tire pump!
Pedal Powered Die Grinder: PPPM I, 400 Watt Victor 12v DC to 110v AC inverter, 12v DC 1 Farad capacitor, 10,000-20,000 RPM Die Grinder
Pedaling Effort: Light to Medium
Pedal Powered Vacuum Cleaner: PPPM I, directly powering 12v DC vacuum cleaner.
Pedaling Effort: Medium to Heavy
Pedal Powered LGB Garden Train: PPPM I, 1.5 Farad Audio Stiffening Capacitor, directly powering an LGB G-Scale Train.
Pedaling Effort: Very Light - Moderate, Depending on Speed and Grade
The fun part of this is you can "feel" the effort the locomotive is making when it hits the grade. Controlling the speed of the train is easy - just speed up or slow down the pedaling. The Capacitor creates "momentum" electronically which adds to the overall effect. Is your consist a little too heavy? Don't just see the action, BE the action.
Pedal Powered Compact Florescent Light: PPPM I, 400 Watt Victor 12v DC to 110v AC inverter, 12v DC 100,000 MFD capacitor, 60 watt equivalent bulb
Pedaling Effort: Very Light (sorry for the pun!)
Pedal Powered Biodiesel Pump (Methoxide Agitation and Transfer): PPPM I, directly powering Hypro 4 roller pump.
Pedaling Effort: Very Light (Agitate) to Medium (Transfer)
You may be wondering if it is possible to do more than one of these activities at the same time with a single unit. The answer is YES. The light, for example, could be combined with any of the other activities. As long as the rider can handle the extra workload, the Pedal Powered Prime Mover can deliver multiple outputs simultaneously!
One of the unique features of this design is that the Pedal Powered Prime Mover is not limited to generating electricity, unlike other Pedal Generator or Bicycle Generator systems. The mounting possibilities for pedal powered machinery are almost infinitely flexible. In the pedal generator movies above, where the Pedal Powered Prime Mover is being used directly as a pedal powered water pump for example, the generator has been removed and the new devices has taken its place. The flexibility is tremendous. In just a few minutes, you can change the Pedal Powered Primer Mover to a pedal generator, or to any of the other configurations you see in the movies. That means one Pedal Powered Prime Mover can serve a wide range of pedal power needs, including whatever you are thinking of right now...
It is more fun than you can imagine to power things by pedaling, with just you as the "Power Plant." It's healthy, and it's green, sustainable energy. What would YOU like to power? Tell me here, and I just might give it a try and make a movie of the result.
One way to calculate how much energy one billion people pedaling such a device 20 hours a week would be:
0.1 horsepower * 1,000,000,000 * 20
Given that a one horsepower equals about 746 watts, then this would be 20 Megawatts per week...
One application would be a new form of health club where exercise is rewarded by dollars or credits for kilowatts. There could be fundraisers, high school competitions, college competitions to see who generates the most kilowatts.
This is more just a concept than something practical at this time...
"Oh boy! I had one of those!"
Fire Fly Energy is coming up with a Carbon Graphite Form battery that replaces the existing Lead Acid battery...
If everyone lit just one little candle..............It’d be pretty dang hot..........
I have to admit, conceptually this is very cool. Heck, I’d definitely be more inclined to get on a treadmill or elliptical trainer if I knew it was hooked up to my house backup batteries and could save me money on my electric bill. Maybe the motivation I need to exercise more (and save money!)?
Hook the pedal generator up to the kid’s TV. You peddle you watch.
Hook the pedal generator up to the kid’s TV. You peddle you watch.
How about a mandatory 4 hour pedaling time per day for all prison inmates?
The possibilities are endless. :)
If a one billion people on the planet would pedal 20 hours a week, the savings would be..
Pedal 3 hours a day to charge batteries? You are smoking something strong.
On the subject of powering a chainsaw with the generator:
If you were to instead take that chain and wrap it directly about the pedalset, would you be able to cut the wood ?
Maybe so, but it would be tough. Once the bladed chain touches the wood, the force necessary to move that bladed chain along the wood increases -dramatically-.
So lets say it was twice as tough to move the chain, cutting the wood. You would need to provide twice the amount of time on the battery to store the amount of energy to cut the wood.
And that’s being optimistic.
To cut a branch I imagine you would need on the order of an hour or more of pedaling.
Am I right ?
I’d prefer a home nuclear reactor. It could be engineered to last decades and fit in the area of a hot-water tank.
If a one billion people on the planet would pedal 20 hours a week, the savings would be..
Would this be a new service class of people? One billion people pedalling to preserve algore’s opulant lifestyle?
I have never understood why all the bikes down at the health club need to be plugged in to work. They have all cords run along the floor, that have to be taped down because they are tripping hazards, etc. Meanwhile on top of the bike you have somebody sweating like crazy and generating all this energy. Certainly enough to run the rinky-dinky display, logic circuits and resistance adjustment.
They would be Deltas, of course.
It would probably be greener just to kill them outright and use horses, though.
It's essentially a generator with a variable load that you can clamp a regular bicycle into for training on days when the weather is too crappy to ride outside.
But, it doesn't do anything useful with the 200 or so watt-hours of energy I'm about to gin up. It just wastes the energy as heat.
Of course, being the environment-abusing capitalist gas-guzzling global-warming inconsiderate conservative that I am... I kinda like that. :-)
Ah yes, the movie : SOYLENT GREEN starring Charleston Heston...
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