How Effective Are Human-Powered Chargers for Everyday Use?

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Human-powered chargers can vary significantly in design and efficiency, with examples like bike-powered chargers being common. Understanding the efficiency equation is crucial, as it defines the relationship between input power (P_in) and stored power (P_stored). A system with 0% efficiency would require infinite energy to store any finite amount, while 100% efficiency means that the energy supplied equals the energy stored. The discussion emphasizes the importance of deriving the efficiency equation to analyze the effectiveness of these chargers. Overall, human-powered chargers can be practical, but their efficiency is a critical factor in their everyday usability.
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Homework Statement


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Can some one please help me out on this, i can't seem to get my head around it.

Regards,
Rob
 
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tell me what you've done so far.
 
do you know the equation for efficiency? if not, do you think you can derive it? if a system were 0 percent efficient(0.00), you'd need to supply infinite energy to reach any finite stored energy. If the system were 100% efficient (1.00), you'd need to supply Z joules to store Z joules. Can you think of a relationship between P_in and P_stored that relies on the 0 to 1.00 representation of efficiency that would produce the end behavior we just explored?
 
Hi Sorry about the late reply i have been away.
I have not managed to do any thing on this question it has stumped me from he start.
It says a human power charger is used but not what charger so i am assuming i can make on up? for instance a bike powered charger?
Any info to get me started would help me a lot.
Regards,
Rob
 
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