25mV Joule Thief powered by peltier merely using our body heat -Free energy 24/7

[conradelektro]

@acmefixer: I looked at your blog http://rustybolt.info/wordpress/?p=5912 . According to my tests the 4:100 ratio on a toroid seems to be the best for the 2SK170 transistor (or for 4 of them in parallel). I even got the impression that 8:100 was slightly better (brighter LED at 50 mV, and for sure at 100 mV).

The coils are not the problem for even lower Voltages, it is the transistor. And one would have to go for a two stage circuit, if the power is there, which needs to be 10 mA in order to get 100 µW with 10 mV. About 100 µW is necessary to make a LED glow, starting with 1 mW one can claim that the LED shines (and one has to provide at least 2.2 Volt).

For me that concludes my work on this circuit for the moment. In Spring I will test several earth batteries with magpwr's circuit cast in resin in order to make the circuit weather and water proof. I want some glowing LEDs in my garden.

The earth batteries I have in mind (two different metals like copper and aluminium or galvanised steel) give at least 200 mV, the problem is Amperage. There are a few threads about earth batteries and I have to go through them to recall the ideas put forward. I do not want to use magnesium (too expensive and it corrodes pretty fast).

In case a reader knows a fairly good earth battery by heart, I would appreciate some hints. Magpwr's circuit opens up new possibilities because 50 mV would be enough (in case 2 mA can be drawn).

At the moment I have two 0.5 meter tubes (10 mm diameter) in the garden, straight down next to each other (copper and aluminium). They show 320 mV and 20 µA short circuit current. This is way too little power for a LED. I will try a copper pipe and a galvanised steel pipe (which I have yet to buy).

I will also try a good earth connection (2 meter long copper pipe straight down) and an antenna wire thrown over my wooden garden shed (or even wound around the shed at roof hight). In the Joule Thief thread there was some discussion about "ambient energy receivers", see http://www.overunity.com/6123/jule-thief/15975/#.UQqrGmckQfw, which I will test. Magpwr's circuit might do the trick to light one LED with this power source.

Greetings, Conrad

[gyulasun]

Hi Folks,

Some relatively cheap sources of ferrite pot cores or pre-wound coils:

http://www.surplussales.com/inductors/FerPotC/FerPotC-1.html 

http://www.electronicsurplus.com/LeftNav/Inductors/Ferrite_ToroidCores.cat 

Of course, ebay can also be a good source but you have to "hunt" for cheaper sellers.

Gyula

[conradelektro]

My earth battery Joule Thief is now working:

It needed the ALD110900 (instead of the 2SK170) to make the circuit run on a very simple earth battery. The battery consists of a copper tube next to an aluminium tube driven into the ground (both tubes only 0.5 meters long, diameter 10 mm, about 5 cm distance in the ground). I also put a 1 meter copper pipe and an 0.7 meter galvanised post into the ground, but that was an overkill.

The LED is of course not very bright, but one can see it clearly from at least 10 meters away (in the dark).

See the attached drawing and photos. Note, it does not work with the 2SK170 because it draws too much power, which can not be sustained by the simple earth battery. Even the long tubes are not sufficient.

I will now put this circuit into a casting resin to make it weather proof.

Greetings, Conrad

[conradelektro]

Deleted, mistake!

[magpwr]

Hi conradelektro,

Interesting oscillator circuit using ALD mosfet.

I was curious about the efficiency for the ALD based circuit.
Using :200mV x 250uA (Found in uploaded image)

I used VoltsxI(Amps) =0.2v x 0.00025A =0.00005 watts or 50mW (Current consumption to light led)

I then try to apply for my 2SK170 circuit VxI =60mV x4.2mA=0.00000252 watts or 2.52mW(Current consumption to light led)

But i noticed my circuit current draw is higher for lower voltage requirement although efficiency wise the 2SK170 base circuit looks better.
Maybe it make sense why ALD mosfet is preferred choice for  radio.