Battery management system using Arduino

Abstract

Battery management systems can measure the performance of batteries. Most significantly, they can estimate expected run time under certain discharge conditions. The calculation is defined as the average current coming from the battery multiplied by the time it takes to reach a safe cutoff point of the battery. These two variables, average discharge current and duration, are directly proportional to each other. Using the average current and time multiplied together provides amp hour rating. An efficient and low cost way to measure these values is by using a microcontroller such as Arduino Nano [1]. The Arduino determines average discharge current and can record time to estimate the Ah rating of the battery. After some fine adjustment using designing methods, the system was obtaining acceptable values from discharging tests using a EFest IMR18650 2Ah Li-Mn battery. Using a standard battery datasheet, the proper shutoff voltage was determined to be 2.5V [2]. The test results were within our acceptable range on the printed battery Ah value. The voltages were then plotted in Matlab using a CSV file created by the serial monitor print out from the microcontroller.