Aluminum/silver battery puts out 0.7 Volts from tap water

[mrdovie]

[Jehu]

Yes, it is an interesting thing but not really fulled by water as such. The fuel is really the meterials making up the anode and cathode which means it's just energy storage via refined metals. What you said in the other post was interesting about the urine battery. Unfortunatly this is just using the urine and a poor electrolyte and wasting metals.

I would like to see a 'real' urine battery that only uses the urine itself and not any of the electrode materials inside.

[mrdovie]

I thought about what you said, Jehu, and tried a cloth soaked in vinegar and one in baking soda/water seperated by a paper sheet with aluminum foil top and bottom. There was a small voltage 0.4v or so, as the acid tried to cancel the base. I would like to try this with SS top and bottom and a better diaphram, it should turn into a salt and not use metal so much?

[Jehu]

From what you've said I think the voltage you are getting is from the Al foil. The vineger is reacting with the Baking soda, releasing CO2 and probably stripping the oxide layer off the Al foil causing a galvanic reaction and producing the voltage.

I would tend to think that if we wanted a urine battery that actually ran off the urine, we would need to look at the urea in the urine and a metal that acts as a catalyst as well as the electrodes. The only one I can think of off the top of my head might be Platinium. Gives me something to think about.

[mrdovie]

I wonder about urine/oxygen or urine with nitrogen fixing plants that would take a little at a time and make a voltage potential in the process? They would need to be potted plants or tanks with algae so the voltages could be added up.

[Jehu]

Yes a microbial fuel cell will work but too much urine will kill the algae in it and I don't think that they can supply much current.

My thoughts were on something more 'solid state' rather then relying on something living.

[magnetman12003]

Try making a crystal battery and you will never mess with water again.

1/2 cup of alum, 1/2 cup 20 mule team borax, 1/2 cup of no salt salt, 1/2 cup of epson salts.
Crush all until you have a fine powder and mix the 4 chemicals completely.

Buy a 2 inch wide 3 inch tall copper pipe fitting from Lowes.
Buy a 4 inch tall magnesium rod off Ebay.

Center the rod in the pipe and water the chemicals down till you have a thick pourable batter. Pour that into the copper tube and LET IT HARDEN UP.

Presto- instant self charging crystal battery. Anode is the magnesium rod. Cathode is the copper pipe fitting.
Might last you a lifetime.

[Chris]

How many amps or milliamps does this little guy put out generally? And you said self-charging... does it need to be disconnected from load to recharge? I am intrigued by this tech for sure.