Charge battery using heat?

  • Thread starter mishima
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  • #1
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Main Question or Discussion Point

Hi, I don't know so much about electronics but...

I know when you have a junction of two metals that is heated you can get a small voltage. Like wrapping a piece of wire around a nail and holding a flame over it produces a very small but measurable voltage. This is a thermocouple as far as I know.

Now I've heard different metals can produce larger voltages. I was wondering if it might be possible then to make something that could use heat to charge a small battery. It would only have to be enough to light a single LED for 4-5 hours.

So, you could put the junction in some charcoal that is burning all day (like charcoal ovens in 3rd world countries), and then come nighttime have a battery that has enough charge to make a light for you.

I don't really know how a battery charger works, I'm just wondering if something like this is possible. Thanks.
 

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  • #3
NascentOxygen
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So, you could put the junction in some charcoal that is burning all day (like charcoal ovens in 3rd world countries), and then come nighttime have a battery that has enough charge to make a light for you.
No matter what metals you try, one junction doesn't produce anywhere near enough voltage from realistic temperatures to charge a battery. You need lots of junctions.

I have read of these devised around a large kerosene-burning lamp for Soviet peasants in isolated regions to listen to a small radio. Mostly this would be while indoors at night, with the lamp providing meagre room lighting and heating, cooking or water heating, together with the daily propaganda broadcast.
 
  • #4
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russ,
Yes I've been playing with a cheap thermoelectric generator like the one in that wiki pic. Its not really a steady voltage, and pretty small. But if my goal was just to charge a small button type battery for a single LED, could I do it with some kind of voltage multiplier and regulator?

Nascent,
That sounds great, I'll see if I can find anything more about that.
 

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