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I'd guess this is definitly baked somewhere but after
some
(lush) searching i haven't found anything close to this
idea:
Everybody seems to be hyped to get some sort of solar
charger for his travelling energy needs. But solarpanels
are
pretty big and I prefer not to have something the
size of
a
medium-sized notebook just to power my cellphone on
the
go.
On the other hand there are these tiny flashlights that
get
their power from a crank and store excess energy in
some
kind of energy storage assembly.
What i propose is a low-output power generator powered
by the human operator. Energy is preserved in a small
flywheel.
The human body is supposed to be able to produce
around
100W over a longer period with peaks at around 300W.
When i turn a the handle on the generator for 5 minutes
i
get:
100 W * 5 min = 30kJ
If i assume that i can store all of this energy in a
flywheel
attached to a small electrical generator i could power a
cellphone that draws around 3 W (rated at 6V and 0.5A)
for almost forever:
30kJ / 3 W = 2.8 hours
Even at 50% effectively i'd be able to charge the phone
for
more than one hour, enough to do a full charge.
Now i guess the whole device could be made the size of a
dish and weight a kilogram which whould be due to the
size an mass of the flywheel. That is quite heavy for
traveling purposes, but everyone who needs a mobile on
the walk can be bothered to pack another kilo.
So ... why is this not baked anywhere? Do i miss some
curial part? Are the losses due to friction bigger than
what
i estimated? Or does everyone today use one of these
smart
phones that require you to charge them every night?
Human power for your cell phone,but no flywheel
http://www.bionic-power.com/
Does it count as baked if you can't actually buy it? [scad mientist, Aug 30 2011]
Another option that is "almost" available to buy.
http://www.npowerpeg.com/
[scad mientist, Aug 30 2011]
Weza
http://www.batteryj...m/frwefrfopoge.html
Discontinued, but still available at some locations. [Klaatu, Aug 31 2011]
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Annotation:
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//heavy// unless it's hollow and you fill it with water when needed. |
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bonus points for making this leg powered and compact.
possibly some kind of stepper-like contraption |
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// charge the mobile battery // |
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i was hoping that the power could be used for different
purposes too. There where actually two situations that
got me thinking about this: |
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First there was this year's festival summer and the guys
with the big solar panel on there bus ... who weren't
there and we where lacking power. A human powered
generator for illumination and possibly a small
soundsystem would be nice in such a situation. |
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And a wooden carousel at the local medival market that
was powered by two people (including me for one ride).
Payload where 8 persons and all 'vehicles' where made
from wood. There was a double crank in the middle and
we got the whole thing to turn pretty fast for what felt
like half an hour (but probably was just about 5 minutes
;) ) |
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good idea! then there would be the need for barriers
inside the container to stop water motion. |
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// help link: exercise gym // |
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urgs ... i've been stalking the halfbakery for like 10 years
now ... but i never have clicked the help link ... shame on
me |
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i guess i'll just delete this idea |
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far be it from me to presuppose etc. but this seems outside m-f-d territory. |
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Hmmkay ... then i'll keep it :) |
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A related (and maybe feasable) addition would be to
make
a small portable flywheel suitable for 'camping purposes'.
And to use this as a collective collector for our annually
festival camp. I guess there are about 4-5 qm of solar
panels around that charge individual car batteries. On
second thought ... maybe that's a better way after all. |
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But i guess flywheels are something that work effectively
only when build huge. |
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Why a flywheel and not just turn the generator itself? You're wasting energy on the flywheel. |
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//If i assume that i can store all of this energy in a flywheel// I would be making a mighty assumption. |
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You might want to remember that the way you store energy in a flywheel is by accelerating it. You can't just spin it at a constant rate - every time it goes around has to be quicker than the time before. Do that for 5 minutes continuously, and it's going to be going awfully quick. You can't do it in direct drive; there would need to be a transmission of some sort. A CVT with a very wide range, or an awful lot of gears. |
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I linked two almost baked (but not actually available) examples similar to this idea. Neither uses a flywheel, but I agree with others that skipping the flywheel and just storing the energy in a battery would be a better solution. These are nowhere near 100W, but still usefull. |
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Fitting a light cover around the flywheel and filling it with hydrogen (easiest source electrolysis), will not only protect it from dust but cut air friction losses by over 93%. |
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Freeplay made the Weza [supposedly, that was the sound it
made as you stepped on it..."weee-zah"]. 30W power from
a stepping action. I understand that they deployed many to
rural areas in Africa. <link> |
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// needs CVT // i was aware of that fact, altough i am not
sure there many lightway CVTs out there. I like the NuVinci
design, but i do not think you can get much range that way. |
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// Weza // aaah ... definitly baked then :) ... hmm...
discontinued ... but maybe i can hunt one or two of these
things done somewhere. Thank's for the hint! |
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Someone on this site proposed pulling a string to generate
electrical power, I think that would go well with this idea,
it could be a leg powered string or not. Oh it was Things
with Strings from this same category. |
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The advantage a flywheel could potentially have over a
battery is faster charging. Putting a hundred Watts directly
into your phone would probably kill it so you need a larger
battery capacity than you actually use to charge it in a
minute or five. |
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Hmm... that brings me to the question: does joe fat use
'eaten energy' less efficient than bob workout? Or will they
both be able todo the same amount of work just over
different periods of time? |
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//heavy//
//unless it's hollow and you fill it with water when needed.//
//good idea! then there would be the need for barriers inside the container to stop water motion.// |
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A flywheel that stored compressed air for ballast wouldn't need baffles and would still have energy stored after it's revolutions were depleted to warn you that you need to quit holding your chest and wheezing so you can get back in the saddle. |
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// filling it with hydrogen // |
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// compressed air for ballast // |
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You *are* trying to make this go boom aren't you? ;) |
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So? Everything has failure modes. But some failure
modes are more interesting than others. |
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