Abstract:
Abstract: The car starter battery normally provides electrical power for engine cranking, lighting of accessories and feeding the engine ignition system. During any given car engine cranking event, a high current ranging from 100A to 1500A, depending on the engine capacity and starter motor type is usually drawn from the starter battery. With each engine cranking event, there is an associated voltage loss in the battery which consequently leads to battery degradation and ultimate failure. The failure may occur abruptly thereby inconveniencing and at times endangering the life of the motorist. The battery monitoring system in this research used the voltage loss associated with each engine cranking event to compute the state of health of the car starter battery. It has a voltage divider, current and temperature modules designed for measuring the battery’s voltage, current and temperature respectively using a microcontroller on an Arduino Uno R3 computing board. Just before the engine cranking request is made, the battery temperature and open circuit voltage are recorded, followed by the set of current and voltage values drawn during engine cranking. After a successful engine cranking event, the acquired temperature compensated voltage value is subtracted from the open circuit voltage value to get the voltage loss for that particular cranking event. The voltage loss together with a voltage loss threshold value were then used in computing the cranking health status of battery and the result displayed in real time to the motorist over a screen on the car’s dashboard. Of the 2 batteries used in the laboratory and in a car in this research, one of them needed to be replaced since its state of health fell below the state of health threshold while the other battery was in good cranking condition since it was brand new. The motorist in whose car this battery monitoring system is installed will be able to know beforehand about an impending battery failure and so take the necessary precaution in time.
Keywords: State of health, State of charge, Arduino microcontroller, engine cranking event, lead acid battery
