Experimental study of earth batteries

We report successful design, construction and operation of an earth battery as an alternate energy source for low power electric supply applications. Different combinations of metallic and non-metallic solid, liquid and gas electrodes were investigated for maximum potential difference. In view of robust and cost effective use of this natural power technology by unskilled village consumers most suitable combinations of the commonly available metals were selected for further detailed characteristic studies. Combinations of Magnesium anode and Coke cathode; Zinc anode and Graphite cathode; Aluminum anode and Carbon cathode; Zinc anode and Copper cathodes gave 2.05, 1.40, 1.10 and 0.9 volts per cell. Typical rated power of a single Zn-Cu cell was measured to be few tens of microamperes. Small power electronic devices such as calculators, electronic watches, baby toys and cell phones and white light LEDs were operated on site. The voltage level was found to increase linearly by connecting multiple earth battery cells in series like commercial lead acid battery. The load current was found to increase by connecting earth cells in parallel. The source current capacities were also found to increase by increasing surface areas of the electrodes. However, single cell voltage was found to remain constant irrespective of the electrode sizes. This paper reports detailed characteristic study of the most cost effective and accessible metal electrodes earth batteries. Operation of earth battery as a free electricity source was demonstrated successfully.