Multisensor fibre optic for electrolyte density measurement in lead-acid batteries

In order to manage batteries efficiently, it is necessary to know its state of charge. One of the physical parameters with information about the state of charge is the electrolyte density. This paper presents a plastic optic fibre sensor developed for measuring in real time the electrolyte density in lead-acid batteries. The multisensor consists of several optic fibre placed inside the battery at different positions in order to make measures at different heights. An electronic circuit was designed for controlling the light emitters and detectors in order to minimize the effects of the ambient light and temperature.