| Electronics > Beginners |
| Free Energy Hand Crank Generators -- 2.4A/5V Possible? |
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| Undweeber:
the reason 500 is not practical is because most batteries today can accept 13W+ easily and there is no reason trading technology that you need to use for subpar technology that you have to use, a 15 minute workout would charge a phone for half a day (in low power mode), a 1 minute workout could charge a supercapacitor based flashlight. 30W is a lot I admit, but what about 13-15W that has got to be achievable, yes muscles can be conditioned to it also, hand switching isnt a crime either |
| james_s:
Well nobody is saying it can't be done, only reasons why 50W hand crank generators may not exist as a commercial product. You may be able to make one yourself though, brushless motors are cheap and readily available in countless sizes and shapes. Gears, belts and other mechanical bits can be found surplus. |
| amyk:
2.4A at 5V is only 12W, and sustaining 12W with the feet is not hard --- normal walking already takes >100W. |
| Psi:
Hand crank generators can put out up to 400W but that is peak and no one can sustain that for more than a minute or so. etc https://www.electricpedals.com/hand-crank-generator A more typical max power for a person over a longer period is about 50W. Hehe, this is interesting. An electric car, like a Nissan leaf uses about 155 watts per km. So if you had 3 people in the car, all using one of those 50W hand cranks, you would have about enough power to run the car on average. :-DD Or at least you'd have enough to maintain speed. Someone should totally build that, it would be so cool. |
| IanB:
--- Quote from: amyk on September 23, 2019, 01:50:15 am ---normal walking already takes >100W --- End quote --- I think this is somewhat of an over-estimate. Walking is very efficient and humans can walk for a very long time (a whole day) without getting tired. This indicates the mechanical power output to sustain walking is quite low. Mechanical power outputs greater than 50 watts are usually associated with vigorous exercise where you will tend to break a sweat and unless very fit cannot be sustained for extended periods. Mechanical output should not be confused with base metabolic load at rest, which is in the order of 80 to 100 watts. This is not mechanical output, it is merely internal energy consumption to sustain life. |
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