Garbage Power! Organic Batteries

by Jorge Murillo-Yepes B&D’s Correspondent in Grenada

JORGE EXPLAINS how it is possible to make a complete battery from refuse materials using organic matter from fruit to produce electricity when it comes into contact with two different metals inside insulated containers.

Wide-mouthed glass or plastic bottles, or tins are used as containers, strips of galvanised roofing sheets for the negative electrode, copper cable for the positive electrodes, any type of juicy organic matter and salted water serve as the electrolyte.

This type of battery is not as powerful as the dry-cell type, and the current produced is weak. It is therefore necessary to set up minimum of twelve, (must be an even number), of containers for the battery to work. The greater the number of containers the better the voltage: 20 or more containers will power transistor-type radio. The shape and size of the containers may influence the intensity of the current, but will not affect the voltage. The best results are from containers with more than 4.5 litre capacity.

A. Glass or plastic container battery

Fill the containers with the organic material.

1. Strips of galvanised roofing material 5-7.5 cm wide and long enough to fit inside the container without touching the bottom form the negative pole

2. Thick electrical cable or copper sheet strips serve as the positive pole. At no point should the two electrodes of the same cell be in contact.

3. Place the containers in wooden box forming square alignment and connect the electrodes as follows: negative pole of cell 1 to positive pole of cell 2, negative pole of cell to positive pole of cell 3.... the positive pole of cell 1 and the negative pole of the last cell are connected to the radio.

Failure in electricity supply can be due to:

- error in the order of the connections;

- a bad contact between the consecutive poles or cells:

- a contact between positive and negative poles within the same cell;

- too little salted water in the electrolyte.

Keep the battery outdoors (protecting it from rain and sun, and out of reach of children and animals). This avoids unpleasant smells and flies, and has the additional advantage that the conduction wire serves as an antenna. A 2.5 cm deep top layer of coconut fibre, grass, paper or sawdust can be used in each cell to prevent evaporation, smells and insects breeding in the organic matter.

Conduct the current to the radio using thick electrical cable (telephone cable is excellent).

The battery will last as long as the galvanised strips, organic matter and saline solution last. To renew the battery change the strips and add more garbage and salted water to each cell.

B. Tin container battery

This type of battery is simple to make because the container acts as the negative pole.

1. Using a minimum of twelve 4.5 litre tin containers or 20 one litre oil tins, make hole in the upper side of one of the walls of each container.

2. Connect copper cable from this point to the positive pole of the next container and so on. There should be no contact between the containers

3. It is advisable to put piece of plastic in the bottom of each tin before filling it with organic material to avoid contact between the poles.

The battery must be placed in a safe location on a plastic or rubber sheet for electrical insulation. This type of battery lasts as long as the containers, the organic matter or the saline solution.

The design of this form of alternative source of energy was developed by the ‘Federacion Nacional de Cafeteros de Colombia’.

* Please see the original journal article to see a diagram of the two battery types