Battery Monitoring System (BMoS) is an electronic system that monitors rechargeable battery cells or packs with various parameters, such as battery voltage, current and State-of-Charge (SoC). This system can be used to avoid overcharging or over-discharging of batteries to increase its shelf life. However, BMoS on the market is very expensive and not suitable for low cost embedded systems. As the Arduino Uno is widely used for low cost microcontroller boards, easy programming environment, and open-source platforms for building electronic projects, therefore, this study focuses on Arduino Uno BMoS based system. This system consists of current and voltage sensors, an Arduino Uno microcontroller and a liquid crystal display (LCD). In order to develop this system, there are three objectives to be achieved. First, the relationship between input and output of the sensors must be derived mathematically. The mathematical expression obtained can be verified by connecting and disconnecting the circuit with load and monitoring the value of output sensors. Then, a complete prototype of the BMoS was developed by connecting the LCD, current and voltage sensors to the Arduino Uno microcontroller. The complete prototype was tested using an 11.1 V of Lithium-ion battery and a DC motor as a load. From the results, the current sensor shows zero value when no load is connected as no current flow. The LCD also displays 11.1V of battery voltage when fully charged. Using the developed system, the user can monitor the current, the voltage and the SoC of the battery to ensure the battery is not overcharged and overused. The development of the BMoS can help to monitor the operation and performance of the batteries in any electronic systems. At the end of this study, the complete BMoS prototype gives benefits to the user and makes work easier.