Wet Cell Batteries
Design:
an example of a wet cell battery though the appearence isn't always the same i choose the simple wet cell battery
Basic wet cell sandwich:
Bottom: 1 inch square of copper flashing.
Middle: 1 inch square of cloth, soaked with salt water.
Top: 1 inch square of galvanized steel flashing.
This constitutes one complete cell which I have found to produce almost exactly a forth of one volt on my meter. If you make a number of these cells, you can connect them in series by stacking them one upon the other until you have the desired output.
Make sure that you stack one complete cell upon another, such that the galvanized steel top of the base cell is in direct contact with the copper plate of the next cell up.
Here is an illustration of a three volt pile. This would be the starting voltage for the common LED lights that are used as indicators on electronic equipment.
The less noble metal (galvanized steel) is the negative terminal AKA anode, and the more noble metal (copper) is the positive terminal AKA cathode. This is important if you intend to demonstrate the power output with an LED, because the light emitting diode is just that...a diode, and allows the current to flow in one direction only.
(picture of simple wet cell battery construction)
(picture of a three volt pile)
Features:
Wet-cell batteries contain lead and a solution of sulfuric acid. Wet cell batteries contain free, moving liquid electrolyte. These types of batteries provide large voltages and relatively high currents, making them ideal for use in telephone circuits and the signal systems in certain types of transportation. The reserve battery used in military applications is also sometimes considered to be a wet cell battery. When assembled, the reserve battery's electrolyte is packaged separately from the electrodes. When needed, the electrodes may be exposed to the electrolyte immediately before use to start a highly energetic electrochemical reaction that provides a short-lived but strong source of energy.
Uses:
Wet-cell batteries are used in cars, trucks, tractors and other motor vehicles to provide the spark to start the vehicle. They are usually about twice the size of a shoe box.
reference: US EPA, Learn About Chemicals Around Your House, Wet Cell Batteries
