Selfsufficientish.com

It's probably a crazy idea - but has anyone thought of producing energy via a kind of exercise bike in the home? I imagine Joe Bloggs pedalling away on his bike in front of the telly, powering the TV and maybe also the computer his wife is using in the next room (logged on to self suffish of course!). It would need something like a battery for storage; otherwise you'd have to pedal furiously when the washing machine comes to the spin cycle !

It could contribute to sustainable energy production as well as to the general health of the nation - no more couch potatoes! Kids might actually prefer not to watch telly if they are only allowed to do it if they provide their own power at the same time; so less dumbing down as well. (Mens sana in corpore sano - as it said above the entrance to my old school!)

Seriously, somebody was offering a "turbo trainer" the other day, and that gave me the idea: you can fix up your own bike to it, and by means of a kind of brake you use it to exercise indoors. Couldn't this be altered by replacing the brake with something like a dynamo? The amount of power created would probably be very small.

I await your comments!

Ina

G'Day Ina, This has been brought up before a number of times and I will leave someone more computer literate that myself to post the links to the correct threads.

In summary, I tried it, and nearly induced heart failure in the operator (myself) to charge an amp or two at 12V. That is not to say it cannot be done with a purpose designed rig but trying to jury-rig one based on an exercise bike did not work for me!

Nev

Ina...

I've thought about this - would love to sit at the computer and pedal away happy in the knowledge that my effort was providing the necessary power. Particularly good in power cuts or cold weather as I could sit at the puter and keep warm by pedalling. I'd be happy just to provide enough power for the puter and a little light so that I could see the keyboard... don't ask for much ;)

I reckon I could get the local kids to do the cycling bit for me, there's plenty of them and it would use up their misused energy!

In my dreams...

We seem to have done this a few times, now. I recently pointed someone to this earlier thread, where I used the back of my favourite envelope to work some figures out. There are some interesting links further down the thread, too.

Thanks very much! My excuse for missing this earlier thread - that was before my time...

I suppose it would have to be something custom made. My new bike has this brilliant dynamo which sits in the hub of the frontwheel (don't know the proper technical term for it in English, and I've not yet heard of anybody having it here, anyway). It doesn't seem to use any additional energy when cycling, unlike the old dynamos, which made cycling a lot harder, and were pretty useless in rain as they slipped on the tyre. It also has a (very small) storage capacity, just to prevent the lights going out as soon as you stop. (It also has a sensor and comes on automatically when it gets dark! ) Something like that, only a lot stronger would perhaps work?

Ina

Sounds interesting Ina! Something like the old Sturmey Archer Dynahub perhaps (Which I have read about but never seen).........

Nev

ina wrote: It doesn't seem to use any additional energy when cycling, unlike the old dynamos, which made cycling a lot harder

Sorry, Ina, but nature just isn't that generous - you can only get energy out of the dynamo if you do, indeed, put energy into it. In fact, because of administration fees and suchlike (well, friction, inefficiency, etc), you will always get less out than you put in.

I think the dynamos of old, which pressed against the side of the tyre, were extremely inefficient, and involved a lot of friction and stuff, so they were akin to putting the brakes on. A hub mounted dynamo will probably be better at using the extra effort you have to apply to the pedals, so it is less noticable.

But as an example of the point, when I was a lad, mum took me round the Science Museum in London, where they had a hand cranked dynamo rigged up to a row of small light bulbs, which could be switched on one at a time. You started off cranking with just one light bulb on, and it was easy-peasy. Then mum switched more on, one at a time, and the cranking got harder and harder until it was almost impossible to turn. This is also why many modern cars, with masses of electrical accessories, have to have two fanbelts driving the alternator - one on its own would break under the strain.

I know, I know... There's no energy output without an input! But it SEEMS to use no extra energy... In other words, you hardly notice the difference when cycling. Well, I don't. Maybe somebody with more sensitive legs would notice it!

And I bet that was good fun at the museum - did you ever switch sides and let your mum do the hard work?

Ina

http://www.stewardwood.org/resources/DIYcyclepower.htm

http://www.windstreampower.com/humanpower/hpgmk3.html

http://www.los-gatos.ca.us/davidbu/pedgen.html

Found these on the net.

Cheers! More reading matter for long and sleepless nights...

i've always wondered why exercise bikes in gyms and other gym equipment isn't used more to generate electricity. - granted the amount generated wouldn't be a lot,. but considering the number of people in this country that go t gyms, it would account for something i am sure.

Only just spotted this thread, and was surprised none of the Aussies suggested looking up Alfred Traeger. He's the chap that made the Royal Flying Doctor Service function by developing the pedal radio. His pedal generators produced 20 watts DC.

Okay, not enough to power a big mains TV but find yourself one of those AC/DC mini-televisions and you'd probably have enough power if you could come up with something similar to Traeger's pedal generator.

Google "Traeger pedal radio" and you'll probably find the specifications. Not me, though, I'm off to bed after finishing work at 9.45pm...

Stonehead