Leclanché cell telephone battery

Leclanché cell telephone battery (incomplete), National Telephone Co. Ltd., UK, c. 1890-1900

This Leclanché cell telephone battery was used in a cotton mill in Rosegrove, Burnley. It was made by the National Telephone Company in the late 19th century when the company held a monopoly over telephone communication in the UK. Despite being incomplete, missing its central electrode and terminals, this example enables a more complete story to be told about the way that telephone networks were supplied with operating current before the public electricity supply was widespread and reliable.

Wet cells were open containers that held liquid electrolyte and metallic electrodes. They were renewed by replacing the electrode and electrolyte. Open containers were unsuitable for mobile or portable use, but they were used commercially in the telegraph and telephone systems. The Leclanché cell did not provide a sustained current for very long. In lengthy conversations, the battery would run down, rendering the conversation inaudible. This is because certain chemical reactions in the cell increase the internal resistance and, thus, lower the voltage.

Powering telephones was integral to their development. The first telephones had a manual Local Battery System where one wire was used to connect the subscriber to the exchange, with the electrical circuit being completed by earth return. Subscribers called the exchange by magneto generator, and local batteries at their premises provided current for speech. But as the batteries were installed in customers premises this was a major expense for the maintenance team and many of the original batteries were wet cells which could leak. These were latter superseded by dry cells, but the expense of replacement mounted as the telephone population rose.