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Shaker Charger Guidance

Lochlyn

Oct 25, 2017
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Oct 25, 2017
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Hey it's a high school student in a research class looking for some assistance.
My group and I are attempting to build something along the lines of a shaker charger for a battery. This we've seen done in the relatively simple circuitry of a shake flashlight, however we need to figure out how to store this energy in a lithium ion rather than a capacitor. size doesnt matter but heat does. The final goal is to put the energy into a battery pack for later use. Any help would be appreciated.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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25,510
You need something which will only allow power to flow from your shaker to the battery.

So you know of a device that can perform this function?

Is the polarity of the voltage generated always the same? If not, do you want to use both polarities? What could allow you to do this?

It might be worth looking at some power supplies built using a transformer. What parts of these circuits perform similar functions to what you have, and what you need to do?
 

Lochlyn

Oct 25, 2017
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Oct 25, 2017
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What voltage can you generate from the shaker charger now?
The device is only theoretical at the moment, but we are trying to obtain the parts to build it.

You need something which will only allow power to flow from your shaker to the battery.

So you know of a device that can perform this function?

Is the polarity of the voltage generated always the same? If not, do you want to use both polarities? What could allow you to do this?

It might be worth looking at some power supplies built using a transformer. What parts of these circuits perform similar functions to what you have, and what you need to do?

I believe we are thinking about using a bridge rectifier to transform to DC current, however, we don't know how to regulate the unstable power output of a shake charger into a normal l-ion
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
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Do a little research on what is required to charge lithium ion batteries.

Try to determine what the fundamental rules are. You'll probably find that some of these rules are unlikely to apply to you (for example, do you think you'll need to be concerned about exceeding the maximum charge current?)

You should be able to boil it down to a single rule. That will make implementation of it easier.

But maybe before that, you might want to characterise the shaker. Firstly, what is the peak voltage it produces into an open circuit. Do you know if it can even generate a sufficient voltage? Once you know this, and assuming it does generate sufficient voltage, what current can it generate into a constant voltage load?

Do you have access to an oscilloscope?
 

Audioguru

Sep 24, 2016
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Sep 24, 2016
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Most people use a charger IC designed to safely charge a Lithium battery to avoid an explosion and fire.
Then they feed the IC with enough voltage and current to do the charging.
Your shaker probably does not produce enough voltage and current.
 
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