Building a pedal power bicycle 12 volt generator, ghetto style

[bucknmusky]

This is the same idea I have been mulling around with for a while. Now Imagine if you will... there are "health clubs" all over with spinning classes, people going nuts on pedal bikes burning as much energy as they can. So why not attach your generator to those bikes and actually recover energy that is otherwise wasted. escpecially with all the electricity those clubs draw, lighting, TV's, water heating their utility bills must be huge all the while they ENCOURAGE people to waste energy.
I leave this up to you, i am just an ideas man If it works out and you become a bike generator mogul Rock On

[Daox]

Haha, me and Higgy were just talking about that the other day.

[Higgy]

Man...can someone lend me some money to start up a gym so I can put this to the test?

[MetroMPG]

See it in action:

YouTube - Pedal bike 12 volt power generator, dirt cheap, ghetto style

[MetroMPG]

Here's a car alternator powered one.

Looks like the "stock" field strength may be causing it to draw more power than the builder can comfortably deliver. He gets winded after about 45 seconds of spinning the pedals!

YouTube - Exercise bike generator uses car alternator

So maybe my wimpy blower motor is a good thing.

Here's another alternator based one that's "not easy" from the promo for the Specialized "Innovate or Die" bicycle innovation contest:

http://ca.youtube.com/watch?v=DLaaunce4JQ

[jwxr7]

Nice video of your set-up. That looks like a very nice old mountain bike .

That Specialized dyno is quite the contraption too.

[MetroMPG]

I like this one too because being mounted to the bike itself, it's portable AND it doesn't disable the bike in any way - although it looks like they put a smooth rear tire in place of a knobby.

YouTube - Mobile Pedal-Powered Generator

[MetroMPG]

Can anyone think of a reason I shouldn't hook my DC/AC inverter directly to the generator output?

One reason I'm using the battery in the circuit is to buffer the output of the generator, thinking it might be hard on the inverter to subject it to voltage that swings pretty wildly as I start/stop & generally pedal at different rates.

But the battery in the circuit battery adds a fair amount of resistance to create X watts of output from the inverter, because I'm also charging the battery (or at least trying to maintain its current state of charge).

[MetroMPG]

Update:

Capacitor needed?

I got one reply to the previous post's question on the Xantrex forum (Xantrex Forums: XPower Plug 175w + pedal generator: battery req'd? ) suggesting I should be using a capacitor (or battery), but didn't say whether it was strictly necessary.

Tire wear!

On another note: I have noticed the generator hub is starting to wear out the sidewall of the tire. So I'll need to take action to prevent that, even though the tread was already pretty worn out for trail riding purposes.

Using it regularly.

I've been using it maybe 1/2 hour a day on average. It's hooked up to a little radio that comes on when I start pedalling. Sometimes I use it to power the laptop to watch or listen to stuff too. (Appropriately, last night I used it while watching: http://www.pbs.org/wgbh/nova/energy/program.html )

Still charging up the junk battery I got. Its resting voltage is in the low 12.5 range now.

[jwxr7]

Originally Posted by MetroMPG

Update:

Capacitor needed?

I got one reply to the previous post's question on the Xantrex forum (Xantrex Forums: XPower Plug 175w + pedal generator: battery req'd? ) suggesting I should be using a capacitor (or battery), but didn't say whether it was strictly necessary.

I would try a large electrolytic capacitor, but you will probably need a fairly large value (the bigger the better, microfarads wise) to make much difference under heavier loads. Just make sure the voltage rating is high enough on the cap. Should be more efficient than a battery as a buffer.
There could also be a concern for overvoltage on the inverter under low loads with or without a capacitor. Most inverters have overvoltage shutdown though. That might be an advantage of having a battery in the circuit, it would better limit upper system voltage.