Using a stationary bike to make electricity
 

Has anyone heard of any ideas on how to convert a stationary bike to be able to produce electricity to feed into the grid? I understand the concept of how solar power is fed into the grid, put what about a bike? I know I wouldn't produce too much energy, but some is better than none. I'm going to use the bike anyway might as well get something out of it if I can.

You would still need an inverter (think solar/wind) to feed it back to the grid so figure a grand plus to install that.....


Human Power Generator -- Generate electricity yourself

Human Power Generator.The Pedal-A-Watt Stationary Bicycle Generator.

Human Power Trainer -- Windstream Power

Bicycle experiment

I ride a stationary bike whenever weather won't allow me to ride the real deal. I thought of configuring the bike to generate power to watch TV while pedaling. So I did math and finally concluded that it would never pay for itself. The electrical power that I could produce would be on the order of a penny a day, or not even that much.

The place that a generator on a stationary bike makes sense is if you have no electrical power, i.e. in your cabin in the hills. Or if you want to power a TV or stereo and use them as your incentive to do the exercise.

Consider that 1 horse power is 740 watts (or there abouts). That is 3/4 of a KW. If you can pedal at a rate of 1 HP for 1 hr. (you cannot) you could produce maybe 7 cents worth of electricity (@ $.10/KWH) if your machine were 100% efficient (it would not be).

Realistically you might produce 1/4 that much power if you are in really good shape. Your equipment and the transfer from pedal to electricity and then through the circuitry required to change it to 60Hz AC is probably gonna be 50% efficient at best. You are now looking at 1/8 of 7 cents for an hour of very hard pedaling. Not even a penny an hour.

Even if your equipment cost you a mere $100 it would take 10,000 hours of pedaling to break even. In that many hours your equipment would probably need replacement. You would never break even. In fact, my guess is that it would be a considerable net loss.

From what I have seen an adult in decent shape can put out around 75-100 watts of usable electricity on a bicycle with a generator on it, if you built it I would say that you should use a synconise motor as a generator and gear it so that motor starts to generate when you are pedaling around 70 RPM as that is a nice pace, then have a switch that doesn't make a connection until you hit that speed, this would do away with an inverter and everything else making it really simple.

saunders1313 -

I have always wanted to power my TeeVee with a bike, but I'm too lazy to get it done.

Wasn't there a post/thread on a fitness center in China that gets it's power from it's members?

CarloSW2

Didn't they prove this on Gilligan's Island? Not a new idea then either I would suppose. Didn't early radios (WWII) have hand crank generators?

Yes, and they still have hand-crank generators for a lot of emergency devices such as radios, sirens, lights and even a cell-phone charger. (I've got HC lights for my car and house) I'd use the stationary bike just for the exercise. If it could provide enough power for a fan or radio, that's just gravy for the goose.

If this could be done it would be great for all the fat kids and their xbox's. you can play video games all you want if you charge up your battery first. I can then see the fit kids sell themselves to power the lazy ones and profit. Maybe it wouldn't work, this is the US.

The idea of using a stationary bike to generate energy is being done here in the Philippines. In a City Jail to be exact. The inmates are required to use the stationary bikes to charge a battery that powers their lights at night. They do take turns and are required to do this. The article can be seen here Jail guard’s invention saves on power - INQUIRER.net, Philippine News for Filipinos with the photos and all.

Just an idea I wanted to share, since they are using an ordinary outdoor bike I believe it won't last in the long run. Wouldn't it be a great idea if they purchased used stationary bikes (buying a new one costs $$$) and use the recumbent stationary bike instead of the upright stationary bike (for those who doesn't know the difference check this site used stationary bikes it has photos of different kinds of stationary bikes) to maximize the usage of the bike since it is more relaxed. What do you guys think?

You forgot to factor in the fact that being as skinny as Tiffany Yep would improve your MPG and that during the winter, you'll stay warm and save a lot of energy by reducing heater use. (Conversely, during the summer, it would increase A/C use and not be worth it, unless it's evaporative or hybrid.) And for some, just being skinny like Tiffany Yep is a big benefit in itself.

Although it probably would make even more sense with a load that is already mechanical in nature, such as an air compressor. Now you're comparing the cost of a set of pedals to the cost of a motor, and it's clear what would win.

Building a pedal power bicycle 12 volt generator, ghetto style - EcoRenovator

I thought about this a while back, but i thought a little deeper into it :D My idea was a Gym that all the equipment was hooked to generators. The amount of energy people burn at a gym would be measurable I am sure :thumbup: If you worked out enough it could even pay for your membership?

hahah, that gave me a good laugh

I saw a program where they took an old washing machine motor and stuck it on a bike, I think they ran it backwards but they managed to light up a light bulb. I like the gym equipment idea, I also thought about this and wondered why no one has never connected all the rowing machines, treadmills and stationary bicycles to some kind of generator. Someone should design this kind of unit that just plugs into the wall and turns your electric meter backwards. I know a few people that would be riding it all day long.

Cordless drills make cheap little generators, just need to find something to chuck it up to. They already have the gears to up the rpm.

chrisgerman1983 -

Here you go :

Chinese Seniors at "Outdoor Gym" Generate Electricity For Local TVs : TreeHugger
Universities generate electricity in the gym - US news - Environment - msnbc.com
HUMAN-POWERED GYMS in Hong Kong | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building

CarloSW2

Powering laptop or tv with pedalpower alone might also lead to healthier life when your hours of using those devices would require quite bit of pedalling. For laptop half hour pedaling might give 1 hour computer time, with tv it might be hour for an hour at max, probably more pedalling than watching tv.

If it would be for exercise it would be just a gain to be able to recycle some of spent energy, also it would give bit perspective of how much work it is to produce electricity and also might lead to better ways of using electricity as one would value it more.

I would forget grid however, just charging battery and use battery to power equipment, that is how I think it would be most beneficial.

Lights in my house that I use consume total of ~18 Watts, as I use LED lights and even those I use sensibly, not emotionally, so I could power quite many hours of illumination by such generator thing.

I'm totally out of shape, but I can peak over 350W for very short period of time, 150W for hour is perhaps bit much for my abilities, but 100W surely.

I would perhaps choose adjustable charge controller so that one could adjust resistance by adjusting how much charging is done.

Rare earth magnets and custom generator might be nice way to get good amount of charging with little as possible resistance, like with DIY wind generators, that way also rpm for generator might be easy to adjust to suitable level, or perhaps by using some gearing, however one should keep losses in mind.

I would build one from real bicycle though, those stationary bicycles are not necessarily best for ergonomy and one might get more power output with real bicycle, also it should be possible to use those trainer stands to support the bicycle, then just use custom rear wheel that is the generator.

jtbo -

My assumption would be a very small tv. Hmmmm, maybe that could be a goal. Start with a small tv and move up to a large tv. You'd know all the tv junkies by their massive legs of muscle.

CarloSW2

We have here LED tv system today, so power consumption is a lot less than those traditional units, even traditional TV was around 100W average, I believe, but LED models can get to that power consumption in fairly large size.

In US TV size has been larger typically than in our country, so there power consumption of TV has been probably higher. 32" is large TV here, when CRT was common typical sizes were 20" or even less, first Flat panels were not larger than 23" from those typically sold, but I guess in US those were used at toilet if even there, so there can be bit of difference in power consumption.

I have 27" computer screen now, no TV at all, but this screen is bit larger than typical, good for my old eyes and has LED technology, so power consumption is not very huge for this size, with laptop + 27" monitor it is around 100W and as laptop is around 40W that is 60W for monitor, should be around same for similar sized TV, which should be fairly easy to produce by pedaling.

Even modern Plasma models should use relatively small amount of power, but don't know much from those, it might be that they stop making those as people buy so little of them, there was news about sales being less than 50% from what one large manufacturer was hoping to get.

guess the idea wasn't that original :o Another thought on maybe making the bike power more efficient would be to keep the drive tire on it and run the generator geared off the wheel somehow? that way you could fill the tire tube with water or cement so that you could have a freewheeling wheel that would keep momentum, if you stopped peddling for a second. that way you could get more consistent output from the generator? I like the cordless drill idea :thumbup: I have access to a bunch of them with batteries that wont hold a charge. Is there anyway that a charger could be used backwards as an inverter? hook the drill directly to the charger bypassing the battery?

There is usually losses involved with rollers that rubber tire rotates, tire flex is already a loss alone, as power levels are fairly low any loss, even small one can be considered something to avoid.

Flywheel might store energy, but also it takes that energy when accelerating, so it would not be free energy, but I don't know if it could be used to store peak energy output from legs so that it could be extracted with perioid of time, it will be very little energy however as peak power can be produced only short time and needs long recovery perioid.

Flywheel is most suitable for power sources that are giving you just one pulse every now and then, like a rowing, now there you could put your legs, arms and whole body to work, so that you could work with higher output, freewheeling flywheel would be then be one that you spin with every pull, this way one could get away with heavy flywheel as whole body can peak quite impressive amount of power, when one is up to a speed, then one could just maintain that speed which would be less work, but rowing generator would really require a flywheel.

With bicycle generator one should learn skill of spinning, that way power output would be consistent and one could spin generator longer period of time as workload is more evenly spread across different muscles.

Also higher spinning speed should be good for long sessions as with slow spinning speed one is using muscle's local energy and with higher spinning speed with lighter load, one would be burning fat that is much more available.

In strongest man competitions they did not use bicycling to pull heavy machinery, it was more like rowing motion, I believe that is way to get one of the highest peak power levels from human body?

[ Is there anyway that a charger could be used backwards as an inverter? hook the drill directly to the charger bypassing the battery?[/QUOTE]

Not sure about that, you will need to add a diode(I think - check valve) so the electrity only flow away from the drill, use it to charge a 12v computer battery backup(or just a marine battery and invertor), use that to power your TV or what ever. Just need to peddle fast enough to get 14 or so volts to charge the battery. if 10-18 speed bike is used, friction drive the drill chuck off rear wheel and monitor voltage output to find the best gear.

I'm guessing the charger must have some diodes in them otherwise I would think they would drain the batteries once unplugged.

Some good info can be found here.

Low-tech Magazine: Bike powered electricity generators are not sustainable

And.

Low-tech Magazine: Pedal powered farms and factories: the forgotten future of the stationary bicycle

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There is one method of bike riding that makes huge financial sense. That would be acctually riding a bike to get some place as opposed to using gas to carry you and 2 tons of steel to do the same.

I bike commute. During the summer I try to do it most of the time, but, in reality, it's closer to half the time. It's 25 miles round trip and it adds less than an hour to my work day. At 3.50 a gallon, I can hypermile my ranger up to maybe a tad more than 25mpg. So, it is better than 4 bucks saved.

To anyone out there that can bike commute, I really can't recommend it enough. A 12 mile ride first thing in the morning, makes the entire day go better.

As for using a bike to generate power, I can see maybe doing it to directly power a PC or laptop or maybe to recharge various batteries IF you are a geek and can make your own generator. If you have to buy anything, forget it. Electricity really is pretty damn cheap.