Bicycle as generator/power source?

"Scott Gordo" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

During the winter I sometimes ride on a trainer, and think about how
much energy I'm expending and how it would be cool to harness it to
power, say, my espresso maker.
I finally did a quick google and found this:
http://www.freerepublic.com/forum/a3ab928b76932.htm
which is pretty close to what I envisioned. He uses this contraption to
charge batteries that power devices.
Has anyone seen a marketed version of something like this produced? I'm
not electrical engineer, and for the right price I'd be happy to forgo
the experimentation.
And, yes, I'm well aware of friction light generators. I have two of
them.
/s

Tacx (www.tacx.nl) do 2 versions of their trainers (Fortius and Cosmos I
think) which generate and feed into the domestic mains AC supply. Quite
natty, but expensive.

Skippy

Scott Gordo said:

During the winter I sometimes ride on a trainer, and think about how
much energy I'm expending and how it would be cool to harness it to
power, say, my espresso maker.

Not a chance! 8-) They draw a kilowatt on the heater.

Quoted message said:

http://www.freerepublic.com/forum/a3ab928b76932.htm
which is pretty close to what I envisioned. He uses this contraption to
charge batteries that power devices.

I adapted a small Nippondenso alternator to a CycleOps exercise stand.
The driven roller was about 3x larger than the shaft shown in the
website, it was _still_ hard to pedal against a useful load (a car battery
and a small TV).

Quoted message said:

Has anyone seen a marketed version of something like this produced? I'm
not electrical engineer, and for the right price I'd be happy to forgo
the experimentation.

If you want enough power to run a laptop computer or a radio, human power
might be (sparingly) useful. I'd not want to depent on it.

bob prohaska

Quoted message said:

On 30 Nov 2005 08:37:33 -0800, "Scott Gordo" <[email hidden]>

Quoted message said:

During the winter I sometimes ride on a trainer, and think about how
much energy I'm expending and how it would be cool to harness it to
power, say, my espresso maker.
I finally did a quick google and found this:
http://www.freerepublic.com/forum/a3ab928b76932.htm
which is pretty close to what I envisioned. He uses this contraption to
charge batteries that power devices.

The protagonists of Harry Harrison's _Make Room, Make Room_ (you might
know the bastardised movie version _Soylent Green_), living in Malthusian
overcrowded New York of.. well, actually, pretty much today, IIRC, but
seen from 4 decades ago, use exactly such a device to charge some 12 volt
car batteries that power a small fridge and a reading light or two.

Jasper

bob prohaska's usenet account said:

If you want enough power to run a laptop computer or a radio, human power
might be (sparingly) useful. I'd not want to depent on it.

http://laptop.media.mit.edu/laptop-images.html

Human-powered or AC powered as you choose, laptop costing $100 in
quantities of a million or so. They are considering bringing versions of
this on the market for Westerners as well -- I know I'd buy one at 2-300
or so to take on my vacation.

http://www.prepare-now.com/809.html

Crank-powered radio. Originally developed for the third world, now also
sold for disaster use in the West.

Jasper

bob prohaska's usenet account said:

Scott Gordo said:

During the winter I sometimes ride on a trainer, and think about how
much energy I'm expending and how it would be cool to harness it to
power, say, my espresso maker.

Not a chance! 8-) They draw a kilowatt on the heater.

<snip>

Quoted message said:

bob prohaska

And that's too much for a car battery that's recharged every so often?
(Sorry, I'm just barely above saying "Magic" when asked how many
electronic devices work.)

/s

If you are able to crank along at 250 watts continuous for 4 hours. (Must be
a good rider to do this) you would generate 1 kilowatt hour which would cost
about 16 cents average in the USA. (4 cents per hour) I doubt you will fine
a product on the market with this low of a payback.

Larry said:

If you are able to crank along at 250 watts continuous for 4 hours. (Must be
a good rider to do this) you would generate 1 kilowatt hour which would cost
about 16 cents average in the USA. (4 cents per hour) I doubt you will fine
a product on the market with this low of a payback.

For that kind of money, there's no way you could afford to replace the
calories burned!

Matt O.

Matt O'Toole said:

Larry said:

If you are able to crank along at 250 watts continuous for 4 hours. (Must be
a good rider to do this) you would generate 1 kilowatt hour which would cost
about 16 cents average in the USA. (4 cents per hour) I doubt you will fine
a product on the market with this low of a payback.

For that kind of money, there's no way you could afford to replace the
calories burned!

And there are very very few humans that could do 250 watts continuously.
A healthy human can sustain about 0.1 Hp, which is about 75 watts.

Larry said:

If you are able to crank along at 250 watts continuous for 4 hours. (Must be
a good rider to do this) you would generate 1 kilowatt hour which would cost
about 16 cents average in the USA. (4 cents per hour) I doubt you will fine
a product on the market with this low of a payback.

You'd also generate about 6,000 Btu of heat (latent +sensible) to warm
up the room - or 0.06 therm, worth about another nickel at natural gas
prices... more if you heat with propane.

Scott Gordo said:

During the winter I sometimes ride on a trainer, and think about how
much energy I'm expending and how it would be cool to harness it to
power, say, my espresso maker.
I finally did a quick google and found this:
http://www.freerepublic.com/forum/a3ab928b76932.htm which is pretty
close to what I envisioned. He uses this contraption to charge batteries
that power devices.
Has anyone seen a marketed version of something like this produced? I'm
not electrical engineer, and for the right price I'd be happy to forgo
the experimentation.
And, yes, I'm well aware of friction light generators. I have two of
them.

There are people making pedal-driven irrigation pumps and flour mills for
people in third world countries. The pumps especially have proven to be
very valuable. Here's an example:

http://www.oriononline.org/pages/om/05-5om/Fox.html

Matt O.

SMS said:

And there are very very few humans that could do 250 watts continuously.
A healthy human can sustain about 0.1 Hp, which is about 75 watts.

Really? So if I propel myself, my tent, my sleeping pad and bag,
Trangia stove, food, clothes, etc etc for about 140 km per day at 20
kph average while touring, I'm doing it at 75 watts? 'Cause I'm in
pretty typical shape or worse. I even have non-aerodynamic panniers,
gut, and beard. I'd have figured 100W easy .

Brian Huntley said:

SMS said:

And there are very very few humans that could do 250 watts continuously.
A healthy human can sustain about 0.1 Hp, which is about 75 watts.

Really? So if I propel myself, my tent, my sleeping pad and bag,
Trangia stove, food, clothes, etc etc for about 140 km per day at 20
kph average while touring, I'm doing it at 75 watts? 'Cause I'm in
pretty typical shape or worse. I even have non-aerodynamic panniers,
gut, and beard. I'd have figured 100W easy .

Well at all those science museums where they have a bicycle hooked up to
a generator, they always claim that 1 person power=about 0.1 horsepower.
I've seen similar estimates other places as well.

SMS said:

Brian Huntley wrote:

Quoted message said:

Quoted message said:

SMS wrote:

Quoted message said:

Quoted message said:

Quoted message said:

And there are very very few humans that could do 250 watts
continuously. A healthy human can sustain about 0.1 Hp, which is about
75 watts.

Quoted message said:

Quoted message said:

Really? So if I propel myself, my tent, my sleeping pad and bag,
Trangia stove, food, clothes, etc etc for about 140 km per day at 20
kph average while touring, I'm doing it at 75 watts? 'Cause I'm in
pretty typical shape or worse. I even have non-aerodynamic panniers,
gut, and beard. I'd have figured 100W easy .

Quoted message said:

Well at all those science museums where they have a bicycle hooked up to
a generator, they always claim that 1 person power=about 0.1 horsepower.
I've seen similar estimates other places as well.

A fit cyclist can sustain over 200W for a few hours. But
75W is probably correct for the "average person."

Matt O.

Larry said:

If you are able to crank along at 250 watts continuous for 4 hours. (Must be
a good rider to do this) you would generate 1 kilowatt hour which would cost
about 16 cents average in the USA. (4 cents per hour) I doubt you will fine
a product on the market with this low of a payback.

Again, apologies for ignorance, but say I set up a contraption similar
to the one in the in the OP, where a trainer is hooked up to an
alternator is hooked up to a car battery. To power my espresso machine
(which Mr. Prohaska says requires a kilowatt to operate) I'd have to
ride for 4 hours at 250 watts to create enough juice to recharge the
battery for one hour's use?
I have a hunch there are other variables involved...?

/s

Sounds like I should start a spin class in my apt....

Scott Gordo said:

And that's too much for a car battery that's recharged every so often?
(Sorry, I'm just barely above saying "Magic" when asked how many
electronic devices work.)

A kilowatt on the heater is a lot, considering how long it's on. You're
not gonna get far above 200W output from a bike-driven generator unless
you're in really good shape, which means you'd need to pedal 5 minutes for
every minute the heater is on, assuming perfecrt battery efficiency, so
real-world irt's more like 6-7 minutes per minute.

It can be done, sure, if you get a large enough battery and pedal long
enough. But it's not exactly efficient.

http://www.wilmap.com.au/alice_springs/traeger.html

Pedal-powered radios invented in the thirties in Australia -- think the
Flying Doctors before every farm had its own generator.

Jasper

Scott Gordo said:

Again, apologies for ignorance, but say I set up a contraption similar
to the one in the in the OP, where a trainer is hooked up to an
alternator is hooked up to a car battery. To power my espresso machine
(which Mr. Prohaska says requires a kilowatt to operate) I'd have to
ride for 4 hours at 250 watts to create enough juice to recharge the
battery for one hour's use?

Theoretically, yes.

Quoted message said:

I have a hunch there are other variables involved...?

There are inefficiencies in the system, once you leave the alternator
(which is only 70-80 or so percent efficient at converting motion to
current, and that's at high percentual loads of the maximum, which you
won't get with a car alternator -- you'd do better with a smaller one).

1) you charge the battery. This isn't a hundred percent efficient in
converting electrical energy into chemical energy.
2) You then discharge the battery. Again, not a hundred percent efficient
in converting chemical energy back to electrical energy.
3) You would then typically feed the battery output to an inverter (sold
for powering devices in your car) to make 110 or 220 VAC out of it.
Majorly inefficient at around 70% or so typically.

I would guess that a mains-AC output of 50W-100W for 200W rider output
would be about the range. Espresso machine? Not so much. Laptop/LCD TV?
Sure.

Jasper

Matt O'Toole said:

There are people making pedal-driven irrigation pumps and flour mills for
people in third world countries. The pumps especially have proven to be
very valuable. Here's an example:

People-powered irrigation pumps have been used all the way back to ancient
Egypt, at least. So did the Mayans and other South American peoples. I bet
the new variant is more efficient than a bucket on the end of a long pole,
supported in the middle (lever), or ancient treadmill/waterwheel/screw of
archimedes style device, though.

Jasper

On Thu, 01 Dec 2005 14:42:42 GMT, Jasper Janssen <[email hidden]>

Quoted message said:

bob prohaska's usenet account said:

If you want enough power to run a laptop computer or a radio, human power
might be (sparingly) useful. I'd not want to depent on it.

http://laptop.media.mit.edu/laptop-images.html

Human-powered or AC powered as you choose, laptop costing $100 in
quantities of a million or so. They are considering bringing versions of
this on the market for Westerners as well -- I know I'd buy one at 2-300
or so to take on my vacation.

You can get used, full-sized laptops for <$200, and they will probably
be more capable than the $100 thing with a crank.

Quoted message said:

http://www.prepare-now.com/809.html

Crank-powered radio. Originally developed for the third world, now also
sold for disaster use in the West.

I have yet to see a review of one of these that really abuses the
thing physically or even tests it to its ultimate mechanical failure.
If you're going to depend on something in an emergency, you want it to
WORK. The original one came out about 15 years ago if I recall, and
now there are hundreds of brands of cheap knock-offs. If you're
designing a mechanism to be operated by everyone from children to big,
burly pro-wrestler types, you have to make the thing robust, and that
means expensive. Unless of course you are trying to make a fast buck
from the paranoid, terrorist fearing, gullible American public.

This one (made by the original maker) looks like it has been designed
(and tested) to be reliable:

http://www.freeplayenergy.com/index.php?section=products&subsection=lifeline