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Building a Pedal Powered Generator (and in need of help!)
Hi, I'm in the middle of converting an old exercise bike to generate electricity for my off-grid tiny home. It's turned out to be a little more ambitious than converting a regular bicycle, as the internal workings of the exercise bike are very... unique. But I think I have a solid plan. I just need to buy a gear and a chain, attach the gear to the exercise bike's flywheel, and use the chain to attach it to my generator. Sounds easy enough. I bought a small 12V permanent magnet motor, made for wind turbines, and it has a little gear on it. I just need to find a second compatible gear, and a chain that fits on those gears.

And suddenly, BAM! I've hit a wall. It turns out the world of gears and chains is immense, and virtually impenetrable for a noob like me. Now this may be a long shot, but does someone on this forum have experience with pinion gears, possibly from a small wind turbine project?

I have an 11T pinion gear, and the Chinese manufacturers of my generator can't tell me any more than that. It seems to be 2mm thick. I think I'm missing some crucial information here, like the "pitch", or the "distance between teeth" or something. Its teeth are slightly too close together to fit on a regular bike chain.

Thanks to anyone how might be able to help!
Can you not source both gears and chain from the same place ? ( or the same bike :-) )

David
You only need a chain where you have a lot of torque like the pedal arm. You could use pulleys and a v-belt for the generator end.
Let me get this straight- you are expending one form of energy to create another form?  And while you are pedaling, what other tasks can you be doing?  I would go get a tape drive and build a wind power generator, and save the bicycle for food grinding or something.
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I've built a few pedal generators and repaired a few. Most are based on exercise bikes. One thing I know for sure is that it is better to have a direct drive from the pedals to the generator using chains and sprockets as if they are set up correctly they are the most efficient versus belts or a two stage approach or running a generator from friction on the tire. You need as good an efficiency as it is really hard work to make a useful amount of power. The average person can do 200 watts for a short time and maybe 50 for a more sustained period.
One easy approach from the mechanical perspective is to use an electric bike wheel as a generator as it already has the necessary gears. Regulating the voltage is a bit more of a challenge and could be helped in some instances by rewiring the stator. I managed to run some power tools directly from the gennies which were either bike wheels or washing machine motors. Cheap power tools like drills tend to smoke where as Makita's had no problems. Same with juicers, some smoke, some don't. Easy to charge a battery though and that will also regulate to some degree.

Greg
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HI. For anyone building anything I suggest looking at the www.surpluscenter.com catalog. They have a very good selection of chains, gears, gearboxes, belts, motors, generators, pulleys, etc. and charts to help size them. Actually, it was a Permie, Doug Bullock of Bullock Bros. Permaculture Homestead, who told me about Surplus Center many years ago.
Is it possible to charge enough to charge a battery that would run a water  pump as well as a heat tape to keep it from Freezing?
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That depends on how many watts it is (your appliance) and how long you want to run it for and how long you want to pedal. You would be using quite a lot of your own energy to generate 100watts so how long would you want to pedal for?

Greg
Heat Tape is a resistance load. As a rule of thumb it takes a sizable, and spendy, renewable energy system to run resistance loads. That's why off grid homes usually have a propane dryer, propane range, propane hot water heater, and woodstove. These appliances can take over 1000 watts each. But a small heat tape might only be about 100 watts. Lots of insulation might prevent it from turning on very frequently. Micro hydro power combined with solar would make this very feasible with a fairly small battery because of the 24 hour/day hydro charging power. Pedal power would be a impractical long term solution In my opinion. But a good backup for charging phones and emergency lighting.
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As for heat....there is a Korean researcher who designed a something like a thin mat on the floor that radiates heat using electricity. Similar concept to the korean/chinese "Kang" bed stove that is similar to rocket heated bed concept. I'd like to share more but going to be very busy for the following days....so just google and you might stumble upon it
 

Jeremy Baker wrote:HI. For anyone building anything I suggest looking at the www.surpluscenter.com catalog.
....but why stop there that place is a gold mine ,the things you can make with there what knots[o i forget most people buy the things to replace the things]another of my new fav places ive found is www.bgmicro.com[sorry for the links i spell like well lets just say im lucky to use letters in the right order when it comes to math}as for tooth count and pitch for a chain stop your losing before you get started,as mentioned above you wont be transferring that much torque[but before i put my foot in my mouth you have left out a few important specs.like what voltage are you after and at what rpm do you need to achieve this,the actual foot print you have to work with,and a few more i would consider,but i have a tendency to wander...] friction can present a few problems,but with enough room they can be over come,belts and pulleys have there own quirks too ... the name of the game is efficiency, and the best way to achieve that at first is simplicity and balance .consider the time you have exerted trying to get the spec sheets and chasing down the link count of the chain the width between the links ect.you could have set up a small tram sled mounted the genny added a friction wheel and been off making a charge,and as you did this the time you spent on the bike [i hear there could be plenty] would have allowed you to see and experience the pros and cons and envision a multitude of the what ifs and why nots......[WOW] my wife just pointed out that i sound like a jerk sorry,i was trying to get around to the efficiency example .the long and the short of it the stationary bike to charge a battery bank strait across the board is not efficient,but dont scrape the project on my point of view,broaden yours.instead of a battery bank plug into a direct use inverter,now this is going to sound funny but you can use one of the outlets to run a trickle charger,and another for a different want or need now one action is providing for two more, thats why the foot print is important to know because to make this happen with a smooth transition your going to want to add a transmittion [gear box even spell check didnt know what i meant ]to get more out of less and of course you will have to add a piece to make sure your getting an even charge with minimal surges,but after you get that in go back to the peddles and add weight to one side creating a cammed reaction so your input can be lessened after you get it started .....and now you can see how to mount a genny to your bike..... all you have to do really is be efficient....

 
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Ben Tyler wrote:
And suddenly, BAM! I've hit a wall. It turns out the world of gears and chains is immense, and virtually impenetrable for a noob like me. Now this may be a long shot, but does someone on this forum have experience with pinion gears, possibly from a small wind turbine project?

I have an 11T pinion gear, and the Chinese manufacturers of my generator can't tell me any more than that. It seems to be 2mm thick. I think I'm missing some crucial information here, like the "pitch", or the "distance between teeth" or something. Its teeth are slightly too close together to fit on a regular bike chain..!



So chains come in two basic varieties, metric and "standard". 
Pitch on Standard chains come in 1/8" increments and the first number equals how many '1/8's.  So #40,#41,#42,#410, etc. are all 1/2' pitch (same as bicycle chain). 
A standard size frequently used on go-carts, etc. is a #35 which has a 3/8 pitch , that's probably what you have.  Measure it from the middle of one tooth to the middle of the next.

If it's smaller than 3/8 pitch, then it's probably a 8mm pitch metric chain.
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Here is an NPR article with some info on household bike generation.  What it comes down to is that a regular consumer's house is going to need about 40 people biking to power it, so if you can get your household needs down to 1/40th the average household usage, you might stand (on some pedals) a chance. You are going to need the most energy efficient appliances, and house design.   Go as direct as you can from pedals to generator. 
(1 like)
The hardest part of backyard engineering is building something that works with the parts you have available!

Something to consider... Instead of chains, belts, and gears; how about this:
Fit a rubber strip to the outside of the flywheel. Then get a child's bicycle wheel and attach it to the generator shaft (or another type of wheel with a rubber tire). Fabricate a bracket for the generator so that the wheel is in contact with the rubber strip on the flywheel under tension.

It might not be the "most efficient" setup, but it will do the job for pennies.

To help with visualizing the concept, look into how trommel drive systems are often constructed using motor vehicle tires.
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Peter VanDerWal's info on the chain is great...

However, since you are searching for the chain without any samples to work with... I'd suggest finding a local bearing distributor and take your sprocket to their counter and get their help in sussing out what pitch it is.
Bonus: they can sell you the parts you need! I'd also go armed with the shaft dimension for the bike end (use calipers or a micrometer) so you can get the correct bore on the hub to fit the bike.

You might also find roller chain at a GOOD hardware store, or an outdoor power repair shop, that you might be able to try some different chains to your sprocket...but they won't likely have the bike side sprocket you want.
So, you'd just be "showrooming" to purchase online later...

If you happen to find some chain, sometimes the plates are stamped with the pitch, and that's a great help...
If you measure ten links and divide the result by 10 you can increase your precision, and maybe tell the difference between metric and standard pitches that are close in size.
 

Peter VanDerWal wrote:
So chains come in two basic varieties, metric and "standard". 
Pitch on Standard chains come in 1/8" increments and the first number equals how many '1/8's.  So #40,#41,#42,#410, etc. are all 1/2' pitch (same as bicycle chain). 
A standard size frequently used on go-carts, etc. is a #35 which has a 3/8 pitch , that's probably what you have.  Measure it from the middle of one tooth to the middle of the next.

If it's smaller than 3/8 pitch, then it's probably a 8mm pitch metric chain.



Kenneth Elwell wrote:Peter VanDerWal's info on the chain is great...

However, since you are searching for the chain without any samples to work with... I'd suggest finding a local bearing distributor and take your sprocket to their counter and get their help in sussing out what pitch it is.
Bonus: they can sell you the parts you need! I'd also go armed with the shaft dimension for the bike end (use calipers or a micrometer) so you can get the correct bore on the hub to fit the bike.

You might also find roller chain at a GOOD hardware store, or an outdoor power repair shop, that you might be able to try some different chains to your sprocket...but they won't likely have the bike side sprocket you want.
So, you'd just be "showrooming" to purchase online later...

If you happen to find some chain, sometimes the plates are stamped with the pitch, and that's a great help...
If you measure ten links and divide the result by 10 you can increase your precision, and maybe tell the difference between metric and standard pitches that are close in size.



Thanks for the detailed advice, guys! I *think* I have a 25H 11T sprocket, and I've ordered a larger 25H 80T sprocket for the bike end, and a #25 chain. I couldn't get much help from the local populace, and I eventually just measured as best I could, searched the internet a lot, and ordered online. My fingers will remain crossed until this thing is hooked up and functioning.

Greg Macmillan wrote:One thing I know for sure is that it is better to have a direct drive from the pedals to the generator using chains and sprockets as if they are set up correctly they are the most efficient versus belts or a two stage approach or running a generator from friction on the tire. You need as good an efficiency as it is really hard work to make a useful amount of power. The average person can do 200 watts for a short time and maybe 50 for a more sustained period.
Greg



Greg, I've heard from several people that this thing is going to be difficult to pedal, and thus I shouldn't try gearing it up too high. However, being how I am, I have to take my chances and risk needing to disassemble the thing later on! The exercise bike uses a nice belt to gear up from the pedals to the flywheel. I'm going to try attaching the sprocket to the side of the flywheel, thus gearing it up even higher to the generator. And the belt will be on the torque end, rather than the stronger chain! I'll see how it goes and get back to you. Either it's going to work great, or the belt is going to slip from too much torque, or else my girlfriend won't be able to handle the workout





How much electricity do you want from the pedal machine? If you want just enough for a few led lights and want to spend the hours pedaling, maybe might be worth it.

I think it is a waste of time and resources to generate any decent amount of electricity with pedal power. It's possible, but quite involved. You are far better off hooking the bike to the appliance and grind your grain with a mill. Pump some water, hook it to a sharpening wheel, hook it to a makeshift washing machine. ...................

If you think you can make an 8 ft diameter wheel that runs perfectly straight and spins perfectly and most likely has a fly wheel that is also perfectly true, and you want to spend a lot of hours manually spinning electricity, you might get enough electric to run a few things.

I think finding a temp job for a week and getting a solar panel or two then instead of pedaling electricity you spend time with other chores and let the sun do the generating. 25 years of sun electricity for a weeks work in 2018.
 

ronie dee wrote:
How much electricity do you want from the pedal machine? If you want just enough for a few LED lights and want to spend the hours pedaling, maybe might be worth it.

I think it is a waste of time and resources to generate any decent amount of electricity with pedal power. It's possible, but quite involved. You are far better off hooking the bike to the appliance and grind your grain with a mill. Pump some water, hook it to a sharpening wheel, hook it to a makeshift washing machine. ...................

If you think you can make an 8 ft diameter wheel that runs perfectly straight and spins perfectly and most likely has a fly wheel that is also perfectly true, and you want to spend a lot of hours manually spinning electricity, you might get enough electric to run a few things.

I think finding a temp job for a week and getting a solar panel or two then instead of pedaling electricity you spend time with other chores and let the sun do the generating. 25 years of sun electricity for a weeks work in 2018.



Ronie, I would agree with you that pedal power is generally not as desirable as solar, since you need to be actively pedaling to generate the power. However, one particular permaculture principle that I am drawing on here is that you should always try to make good use of the resources available to you. I happen to have a girlfriend who insists on expending large amounts of energy through indoor exercise. She's like a clock: for 1.5 to 2 hours a day, she's moving unnecessarily and wasting who-knows-how-many calories! Now, what could be more permaculturey than hooking her up to a generator and harnessing some of that energy?

Regarding our energy needs, the two of us live in a 160 sq ft tiny home, with solar panels already providing us with all the lighting we need. We're hoping the bike will give us enough additional electricity to run a laptop and charge cell phones. We'll be using the bike to charge a 12V deep cycle battery, and going DC to DC by using a car charger cord for the laptop. I'm curious to see the ratio between "hours pedaling" and "hours on laptop"!

Hey Ben, Hope it is warm where you are. Sorry, if all you want to do is make enough for phone, then my advice is little value to you. Unless you might think of a way to make a simple mechanical device (clothes washer is coming to mind) you are well in the right zone to have a simple electrical charger for your situation. A deep cycle battery and generator might be more expensive than setting up a barrel that can be turned with your "free" muscle energy that does the laundry.

Best of luck and warm weather to you. Hope to see a follow up as to your experience with the muscle power.
At this time of the year, I would love to have a pedal-powdered generator, as my family and I rely on solar and the day is short. But that is not why I am posting. I have a pedal-powered washing machine. When my husband first made it, he followed directions found on the internet and used a belt to turn the machine. The belt really sucked. It constantly broke and made washing the clothes very difficult. In a re-build of the machine, he decided to switch from the belt to a bicycle chain. The bicycle chain can sometimes work really well. But, it requires a very precise alignment for that to happen. If someone decides to pedal like he's mad when spinning his clothes (I will not name the person who is guilty of this -- but not my husband, who has to repair it when it happens), he throws the alignment off. And then it doesn't work very well. My husband is planning the next re-build. On this one, he wants to switch from a bicycle chain to a scooter chain. I would really like to switch to a gear system and have been looking at the gears at TRI Distribution. ( https://www.tridistribution.fr/fr/spur-gears-and-racks/engrenages-sans-moyeux/engrenage-module-2-sans-moyeu.html ) Only I am also rather confused about what the numbers actually mean.
 

ronie dee wrote:Hey Ben, Hope it is warm where you are. Sorry, if all you want to do is make enough for phone, then my advice is little value to you. Unless you might think of a way to make a simple mechanical device (clothes washer is coming to mind) you are well in the right zone to have a simple electrical charger for your situation. A deep cycle battery and generator might be more expensive than setting up a barrel that can be turned with your "free" muscle energy that does the laundry.

Best of luck and warm weather to you. Hope to see a follow up as to your experience with the muscle power.


At CDG airport, they have pedal-powered chargers for charging mobile phones. Not too many people actually use them, but I do when I'm there waiting (they have some by the train station). It takes about an hour for me to charge my phone.
 

ronie dee wrote:
How much electricity do you want from the pedal machine? If you want just enough for a few LED lights and want to spend the hours pedaling, maybe might be worth it.

I think it is a waste of time and resources to generate any decent amount of electricity with pedal power.



While I agree that you won't generate much power using a pedal power generator, whether it's worth it or not kinda depends on your goals.  A strong rider on a generator made from spare parts might be able to produce 80 watts, your average person perhaps 20-40 watts.
So yeah, not a lot of electricity.

However, if your goal is to get some exercise (say during the winter when it's too cold to be outside) and perhaps some heat (a strong rider can produce 600-800 watts of heat), then you can think of the electricity as a free byproduct.

Even an average person pedaling for 1 hour can produce enough electricity to run an LED all day, which could come in handy during long storms, etc.
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