Measurement of impedance and conductance: myth and reality tested in the field

Over the past 15 years, impedance and conductance measurement techniques have been intensively studied as a solution for rapidly determining the aging of lead-acid batteries. France Telecom, along with various telecommunications operators throughout the world, considers that the measurement of impedance and conductance constitutes a potential solution that should be investigated with a view to reducing the costs and time involved in battery test operations, while maintaining an acceptable level regarding the reliability of the test results. This paper introduces the environment and operation of batteries as currently defined by France Telecom. We then concentrate on procedures for choosing test equipment that corresponds to the requirements of the field, in an environment that conforms to the different uses of lead batteries by a telecommunications operator (telecommunications centers, client sites, mobile network hardware, local loop hardware, etc.). The experiments were carried out in two regions of France and their results are then described. The feedback from the field allows estimation of financial profitability. Beyond the investment gains in new batteries and maintenance time, the results are linked to the number of incidents avoided, and therefore to a reduction in client complaints, as they will not have to undergo interrupted telecommunications network access. The attention paid to the measurement and its exploitation is also a dominating factor. The conclusion will rest on the latest development in battery tests at France Telecom.