Picture of Turn an exercise bike into an energy bike
Why pedal a stationary exercise bike for exercise? Put all that sweat equity to good use while getting into shape. Turn you exercise bike into a power generator to run lights, a TV, stereo, blender, etc. Recharge a 12V battery or drive appliances directly. This is an excellent educational tool for science and technology classes. There are several options for how you design and build it. I'll show you how to build this one and point out other options along the way.

Here's a list of parts you'll need to get started:
- exercise bike, with cast iron flywheel or rubber tire type
- DC motor or generator with magnets, 12Vdc or 120Vdc recommended
- 1/2" plywood, 3/4" will also work
- 6' - 2"x 4" pine lumber
- 4' link belt (or fan belt)
- 1/4" Lag bolts
- assorted screws
- 3/4" water pipe and end caps
- screw band
- wire DC volt meter
- DC amp meter
- 14 ga. wire
- 2' of 1-1/2" PVC pipe
- 1-1/2" sheave (pulley)

Tools you'll need:
- jig saw
- hand saw or chop saw
- router (optional)
- drill and bits
- hacksaw
- file
- wire cutters and strippers
- screw driver
- socket set and ratchet
- carbide cutter
- vise grips

Step 1: Prepping the exercise bike

Picture of Prepping the exercise bike
I prefer to use Tunturi or Vitamaster exercise bikes for conversion. They are well built with a heavy flywheel and good bearings. The frame is solid, but the handlebars may wobble a bit on some models

Start prepping you exercise bike for conversion by removing unnecessary equipment. Most exercise bikes have either brake pads or a web strap that rides on the perimeter of the flywheel. This one has a watt meter hooked to the drag brakes.

On this model, you'll also need to remove the rubber banding from the perimeter of the flywheel.
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PraV111 months ago

I want to make it sir , but i am not aware of electrical terms ......
How much energy does this cycle can produce if i use this for 1 hour /10
hours continously....I am planning to make a cycle where the energy
generated is stored in battery..... How to store this energy and reuse
it ? Does this serves the purposes of daily needs of house ?

mspark4007 years ago
nice Instructable, and good picture very high quality job, btw, the boy in the picture wouldn't happened to be named Charlie would he? just a vague guess
Folks, I have designed a bike generator that is producing over 400 volts at 2500+ RPM.. Need some ideas on how to effectively use this high single phase voltage
Step down transformer?
wingsinger (author)  mspark4007 years ago
Nope, her name is Alexandra. She was nice enough to push a few Watts through my lights for this demo, but she had no interest in pedaling hard enough to run a big screen TV for the Superbowl.
Could you give me exact specs on the motor that you used? I'm new at this and need a little more guidance. Thanks.
Lol, that name was way off :P
yes it know i should have at least been closer by guessing a girls name( i DID think that the person in the picture is a girl) but the guy i know who is named Charlie looks eerily similar
sorry about the mix up lol =)
(eerily similar though, i think he even has that shirt)
wingsinger (author)  mspark4007 years ago
Alexandra is my 14 y.o. daughter. Now I'm curious to see what Charlie looks like.
i don't think he will pose for a pic sorry It's not that she looks like a guy, its that he looks like a girl lol
Nice save... =/
just a little hint mspark, when in confusion look at the shoes.
good one mspark400...
I absolutely love your project. it's close to something i'm hoping to achieve. Do you know enough about electricity wiring in a home to know how to wire a source of power to your home to run your electricity meter backwards safely?
I don't know where anybody got the idea that this would be wired into the house wiring. Also unless you have your kid peddling while you are trying to do the wiring you will not be working with live wires. However I highly recommend for safety that some kind of a box enclosure that can be secured so that small children or pets cannot cone in contact with turning belts and pulleys or electric components. If you use a 12v generator like the author I would suggest installing a cigarette lighter style outlet so as to accommodate the many 12v appliances that come with cigarette plug. I would use a car voltage regulator and a couple deep cycle batteries so that one wouldn't have to peddle the exact speed to maintain 12 volts. If you installed a 12v to 120v ac power inverter you will have some emergency power during a power outage that could power a couple lamps and your TV or computer. A 400w to 800w inverter can be had fore about $25- $50
You really need to consult an electrician in your area to do this. If not done properly you can backfeed to the power company and do some serious damage. I've been in the electrical business for many years so I know this can be dangerous.
For something like this it's not worth the effort. That said it's tricky wiring doing what you want. Dangerous too as unless you call you're electric company you'll be working with live wires.
PhotoMaster3 years ago
I made something similar to that, to help a friend lose weight. Mine didn't generate the power, but used a headligh generator to switch a solonoid I hooked into his TV. Yours is quite clearly better and much more versatile! Great work!!
rsingh34 years ago
Super cool! Ho could I hook this up to like a tv or something? And what type of batteries would you recommend I use to store the energy? And in general how much output can I expect to get out of this guy? Also to a more general audience are the clock kits off of http://wooden-gear-clocks.com good for a grandfather clock? Thanks!
lucek rsingh33 years ago
As for the grandfather clock you could put the mechanism in a grandfather clock but I don't see the point. At that point you are shoving one clock into another.
lucek rsingh33 years ago
For best results a marine 12v battery would be a good idea, Then if you are going to plug a standard TV into it an inverter to switch the DC to AC. Alternately using a DC TV is an option.
lucek3 years ago
Hook it up to a battery and a small TV and you'll get you're exercise in.
PS1187 years ago
Very nice. I LOVED the idea of using the flywheel to lathe itsself!! One comment though. In case there's not one builtin to your generator, you may consider adding a diode. Otherwise, on a full battery it may go from being a generating bike to a motorized, self-peddling bike. (Though I admit that would be more my style of excercise ;) )
wingsinger (author)  PS1187 years ago
Yes, a diode is a must when charging a battery, I should have mentioned that. And if the diode is put in series with the generator, but backwards, the battery would still treat the generator like a motor. Polarity is important. Personally, I'm at the age where I prefer self-peddling bikes myself ;-)
Are you still on line? What is your current rec. for motor generator to use for demo to kids on energy use? Would like to show the difference in effort to power a cfl vs a incadescent. light bulb. Should I be using a 90 vDC motor or a 12 vDC motor. Where and product numbers for these motors. Thanks. Dutch
Excellent. Well written Instructable! We lose power a lot at the island I spend my summers on. I am going to try and rig our stationary bike to work like yours. Ed Begly Jr. would be very proud of you. He is a major supporter in projects that help to improve our environment. Perhaps you could send him a link to your Instructable (he has a T.V show devoted to cool inventions such as yours)
japetopan5 years ago
 I don't get to find the generator motor. Does an alternator of a car work for this?
car alternators are incredibly inefficient. All they need to do is trickle charge a 12 volt battery. They have all that horsepower from the 200 horses ICE engine to kick it around, so auto manufacturers are more concerned with longevity than maximizing electrical output. Plus look at the gear ratio an alternator is on, smaller pulley wheel from a larger one on the engine, means it rotates at thousands of RPMs
You can buy a stepper motor from $35, or visit radio shack for a small toy motor more appropriately sized for one person, rather than 200 horses.
alternators achieve about 50-60% efficiency.
dc generators achieve from 50-80% efficiency.
the rotational speed of the alternator is not important as this instructable already uses a pulley and belt to turn the DC motor(generator) faster than the crank speed of the 'bike'.
yes it should, though I was talking about this type of set up to my father the one day and he suggested a old chevy generator (1950 or so i believe it was) which would work better..... though chances of finding one would be hard or more likely impossible....at least for a decent price
gladys455 years ago
the hair? has no-one noticed it yet? have i entered some sort of time warp?
You are looking at a child who is obviously involved in a very cool project. Isn't it wonderful that creative and clever people share their ideas at Instructables?
that poor bedraggled child, needs more fun in their life.
being used as a human powered generator seems a little harsh....
also, time travel has most definitely occurred.
i noticed
twighahn4 years ago
how would u hook it up to batteries? or an ac inverter?
hedwood5 years ago
 Hello and nice work - the practical and the informational!
Have you considered or experimented with a flywheel in the loop?
I'm a cyclist and we're used to taking advantage of the 'freewheel' effect a rolling momentum brings about.
I've seen a four person static bike that powered a small stage at a festival - that was more than a decade ago - and I still often wonder if this idea is worth merit...
Obviously gears would enable a start up - perhaps even for a very heavy flywheel spinning eventually at quite a clip!.. good bearings being a must.
Basically any experience on a bike and you'll remember - that flush of energy one feels at the mere hint of 'powering off' as it were.
Must say - apart from this fine example and others like it, I've never liked exercise bikes - monotony!.. hence the above....
Any thoughts?
I once read in a bike mag that riding an exercise bike is like watching paint dry.  And watching TV while riding an exercise bike is like watching colored paint dry.  Being a cyclist, I have to agree.
Wow... so creative ideas using such used stationary bikes to get more valuable thing like the energy, can we find like that in market?
what TV shows do u watch? watch Tour de France? if u like cycling
 You are an awesome person for posting this..we all need to power our own computer at least then we would not gain weight..all the health clubs should be doing this I have said this for years!! I used to make jokes I would get a bunch of foster children and put them on bikes not I have the instructables to do this and sell power to third world countries :)

You are helping the planet one person makes a difference!
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