Realcent.org

http://www.instructables.com/id/How-to- ... 3-Pennies/

Now, the question is, can you use a zinc penny on the bottom or would the copper plating interfere with the electrolyte function? If that is the case, how easy is it to remove the copper plating?

In any case it is useful to know for an emergency power source since little LED bulbs take so little power.

Maybe someone here will try a few variations on building a 1.5 volt power source.

If this is true then HCBTT could power up much of the Southwest for several months.

Neat factoid, thanks for posting

"An individual battery cell is a zinc bottom, copper top, and separated by a material like paper or cardboard that's been soaked in an electrolyte. 

From my testing, each cell yields just over 0.6 volts, and around 700mA.  The copper top is positive, and the zinc bottom is negative.  This calculator needs around 1.5 volts, so I used 3 pennies, 3 washers, and 3 pieces of cardboard soaked in white vinegar.  (3 cells x 0.6 volts = 1.8 volts approximately)"

So, the three penny cell would be (starting at the bottom) Zn washer, cardboard, Cu penny, then another washer on top of the penny with nothing in between? The author doesn't say and the pic isn't clear on this either. i am assuming this is the case and that connecting each cell in this manner is just lining them up in series. Am i missing something? or have i got it?