# Crank a Watt



## catsraven (Jan 25, 2010)

400 watt hand crank generator.






http://www.prestowind.com/


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## cowboyhermit (Nov 10, 2012)

Cool, but, all they are showing is using a battery and inverter to run stuff. They are not showing how much it would actually take to charge that battery with the crank Also he says the alternator will last forever  realistically it probably would never wear out with hand cranking but only because of the difficulty in doing so. I like that it has a pulley so you could run it other ways (like off a bike etc) but hard to say how efficient it is.


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## LincTex (Apr 1, 2011)

cowboyhermit said:


> Cool, but - all they are showing is using a battery and inverter to run stuff. They are not showing how much effort it would actually take to charge that battery with the crank.


Absolutely 100% correct.

Using pedal power, it is well documented that a strong, healthy human being pedaling vigorously can put out about 100 watts. Do that for one hour (Whew! I couldn't) and you have 100 watt-hours. (1/10th of a kwh)

Arms have *far* less strength than legs, which means he probably makes more like 25 watts (I am being very generous, since you can only use one arm and not both at the same time with this).
If he COULD do it for an hour, that would be 1/40th of a kwh, but I'll bet that guy can't crank that wheel for more than 15 minutes, that's only 1/160th of a kwh.

That's not a lot of power.

He would be MUCH better off making a bicycle style alternator instead - - but even a pedaling-style alternator just does not make a lot of electricity!!!!


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## hiwall (Jun 15, 2012)

It was very obvious on the video when he never once touched the crank.
Thanks for the vid, catsraven.


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## LincTex (Apr 1, 2011)

I have some little "squeeze handle" LED flashlights, it takes a fair amount of "grip energy" to keep running it, I can't imagine how many hours he needs to crank to run some of those appliances for even two or three minutes!


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