Bike Generator?

Question

I asked a while ago about this, but I there was still some confusion in my mind. My ultimate goal is to use power electric heating coil from human powered bike. I was wondering, I will I be able to create enough power to power the coil?

Here's what I have so far: I took the motor out from an old fan, and I was thinking about directly connecting that to the bike. My question is would that work? If so, about how much power will I be able to get out of it? Am I going to need anything like an inverter? or can I just connect to the two end terminals to the coil, and that would work? Also, am I going to need a diode? Basically, what I am trying to ask is how would I put everything together? I have bits of info, just need to figure everything out.

Also, as for the coil, how does the wattage rating work? I am thinking of using maybe like a teapot coil..

Thanks in advance!!

Answer 1

I have an old bike generator and it's rated 6Vac at 3W, so that's .5Aac. One watt of power is about 3.4 BTU.
You want to derive the maximum power transfer, so if your Gen happens to be like mine your need to calculate load resistance.

R=V/A R=6/.5 R=12 Ohms

Your heating coil needs to have a resistance of 12 Ohms. Now you could wind a coil of wire that would have that resistance. I can tell you how to do it. Or you can go to an electronic store and buy a 12 ohm moisture proof resistor. If it is always going to be submerged heating water, 3to5 Watt rating is plenty, otherwise make it 6Watt. Make sure you cover the leads with heat shrink tubing for insulation, its not critical because the voltage is so low. Connect the leads right across the output of the Gen and that's it. Pedal your bike and the resistor will get hot. About 10 BTU. If you want details on making a coil, email me. Good luck

Answer 2

Well, I think all generators are basicaly the same, be it DC gen or AC gen. Generator is a device used to convert electric power (DC or AC) to kinetic or movement power, or vice versa. The difference is the input/output. AC gen uses AC input/output, and DC gen uses DC input/output. The problem (not just in this case, but with all power plant) is efficiency. If you'll end up using more or same power than the power it generate, then why bother?

As for your case, try reading the power consumption for your fan motor. It should say what wattage it consumes. Then, try pluging it to a socket, and see how fast the axle rotates (this could be VERY tricky). For example, it consumes 40 Watt of energy and the axle rotates at say 400 RPM (round per minute or 400 rotation a minute), than to turn the system around, you'll need to rotate the axle 400 rotation a minute to get 40 Watt of energy (I think that's a lot of work, for so little energy). I'm guessing you're considering this so you won't waste the energy when you're working out with a static bike (I might be wrong).

If you really want to go through this, I don't think fan motor is your best choice. You'll need a motor that's more efficient. One that requires less rotation and generate more power. Try looking at electronic store, and if you still can't find any, maybe you could find a mechanic that has the ability to construct your customized motor.

Answer 3

Cool invention.
I'm not sure if they still have it, but Disney World, like at Epcot Center, a few years back had light bulbs hooked to bicycles to let you see how much energy you could generate.

My conclusion is your legs will be exhausted by the time you create enough energy to bring a liter of water from 25°C to 100 °C. Calculate how many calories (joules) that is. A bet a good bit.

Answer 4

bike generator is d.c. fan is a.c. it will take other bits a pieces to get it to work.