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charging a single NiMH aaa battery from a supercapacitor

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jeromekang

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hi i want to charge a single NiMH aaa battery. So the flow of the circuit that i am thinking of looks like:

piezo transducer -> ac to dc -> supercapacitor -> battery

so my question is... can the supercapacitor be connected in parallel with the battery to charge it? the supercapacitor is 10F 2.3V and the battery is 1.5V.
 

The only meaningful reason to use a Supercap as intermediate energy storage would be an input current above the rated charge current of the battery. I doubt that this is the case with a piezo transducer.
 

correct me if i am wrong..so what you are saying is that i can directly charge the batteries without the supercap? what if i used an ordinary electrolytic capacitor?
 

The energy output from a piezo transducer is so small that it will take weeks or months to charge an AAA Ni-MH cell. Then the piezo transducer will fracture from fatigue.

Are you the guy on the other website who is trying to harvest the energy from a piezo BBQ lighter?
It might fail after a few hundred clicks. You might need millions of clicks to charge an AAA Ni-MH cell.
 

Hi Audioguru,
I can not agree with the cracks aspect;
if you will try properly dimensioning_it will work over many moths, but these is not a simple job!
We can find lot of dissertations over that_ I believe, its not a random effect, its really complex subject.
K.
 

    jeromekang

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The piezo BBQ lighter example clarifies, that it's necessary to thing about utilizable mechanical power and impedance matching.
Without elementary mechanical and electrical engineering knowledge, the case is - hopeless.
 

You can buy a very expensive "energy harvesting" IC. Its max allowed input is 500V but a piezo BBQ lighter has an output of thousands of volts.

They do not show how to reduce the voltage without wasting a lot of the tiny amount of power.
The energy harvesting IC efficiently reduces the 500V down to a few volts. Maybe a watch can be powered.
 

@Audioguru no i'm not the guy on the other website

@karesz thanks for the links appreciate it :D
 

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