Human Bicycle Power Generation: Who needs fossil fuel when you have legs

bicycle_power_windstream I was surprised to see that one of my most popular blog posts has been on Bicycle Power.  In that post I said that the average power that a cyclist in excellent shape will be able to put out over the course of an hour is probably right under 300 watts.  The majority of people are probably closer to 150 watts. So what can you do with this energy? There are several companies out there who make bicycle generator kits for use at home.  A few of them are: econvergence, scienceshareware, and windstream power.   They all utilize the same concept:

  1. Put your bike on an indoor trainer
  2. Align the back wheel so it makes contact with the generator wheel
  3. Get on and pedal like mad!
  4. Use the generator to charge a battery

I love this concept because a) I'm a renewable energy nerd and b) I'm a cyclist.  I would love to know that I'm providing clean power (even if it is just a small amount of my daily consumption) and improving my fitness at the same time. Once you charge a battery with your bike you can use it to power your phone, laptop, camping light, etc.  Pretty much any small electronic devices.  If you really want one of these things for utilization, then they would be most useful in remote cabins or somewhere that is off the grid, but still may require a little power every now and then.  In any case it's a great backup if it's the middle of winter, your off the grid, and your generator won't start! There are two things I would like to see though:

  1. Better data logging capabilities (more use for the Cyclist)
  2. Improved charging solution (more use for the renewable energy nerd)

GoBe_solarbriefcase_batteryCurrently the companies are using third party batteries to connect the bicycle Generators to, but I would like to see something like the image on the right from GoBe Solar.  GoBe's package is a solar briefcase and a nice compact battery that has a USB outlet, DC outlet, and AC outlet all in one.  The solar briefcase from GoBe is only 10.5 Watts, over 1o times less power than what someone on a bike can produce.  Of course the main difference is that you can leave the solar panel in the sun all day, but you can only bike for so long.  Also, the solar panel uses free solar rays as fuel, while you have to fuel a cyclist with bananas and peanut butter sandwiches. *update - check out the Fenix ReadySet portable power storage device that is about to have a bicycle generator device. I'm sure we'll see a nice solution like this in no time though.  Just a few years ago there weren't any home energy monitoring solution, and now there is a whole list of them. If you want to read more about this topic, I highly recommend the article Bicycling Magazine had in November's issue titled High-Voltage Workouts.

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am interested in knowing the average speed (RPM) at which a good cyclist can ride this bicycle
ckmapawatt's picture
Well, it depends. When riding at full speed, a cyclist will probably be spinning between 80-110 RPM. But it all depends on what gear the cyclist is in. It's harder to turn a bigger gear faster. On the road, a cyclist will be pedaling at a lower RPM when climbing (because it's harder to turn) and a higher RPM in sprints or downhills. The great thing about this setup is the cyclist can determine which combination of gear ratio and RPM will produce the most power!
I'm an average weekend-warrior road racer, and there's no way I could dream of putting out 300 watts for an hour. 150-200 watts, sure, but 300 watts for an hour isn't just a cyclist in excellent shape, it's a cyclist who's probably racing domestically at the semi-pro level. I'm still interested in getting something like this set up on my indoor trainer, though.
Reading this it would be interesting to find out the efficiencies of the bike by fitting a powertap hub or SRM crank to measure the wattage the rider is outputting and then comparing that to the amount of energy going into the portable power pack.
Be good if health clubs could adapt these to their stationary bikes. My club only has six, but over the course of a day, they are probably used several hours. Ideally, it would be great to have it returned to the grid, but if nothing else, they could probably provide battery power to power their own graphics.
Art, Look at the Bicycling magazine link at the end of the article. It talks about 2 companies that are doing what you are suggesting. The biggest reason why you don't see it is because of $$$. Now, if more people told the gyms they would like to see this type of device, I'm sure we'd see more of them.

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