REFRACTOMETRIC FIBER OPTIC SENSOR FOR IN-SITU MONITORING THE STATE-OF-CHARGE OF LEAD ACID BATTERY

摘要

In-situ monitoring of the state of charge (SOC) of lead acid battery is important to understand the residual electrical energy. Usage of battery reduces the charge content of the active electrolyte which in turn changes its refractive index. This paper reports refract metric fiber optic sensor developed for on-line monitoring of SOC. The sensor is designed in such a way that it can be easily fitted in any cell of lead acid battery. The SOC of battery is estimated from sensor output. The battery performance parameters of the battery such as terminal voltage, discharge current, ampere-hour, battery temperature, SOC and Depth of discharge using fiber optic sensor output of battery are monitored for given electric load. The data is recorded continuously by data acquisition card USB 6009 using Lab VIEW Platform. Concurrently specific gravity of active electrolyte is measured using suck type of acidic hydrometer. The set of experiments are carried out for different discharge current by varying electrical load and SOC of the battery is monitored. After comparing the results for SOC of the battery with the conventional methods such as coulomb counting, terminal voltage and acidic hydrometer, it is concluded that developed sensor output is direct measure of SOC of battery.