ABSTRACT Since nowadays, especially in the automotive field, lead-acid batteries are getting more important, a good diagnostic of the batteries is becoming essential. The aim of this thesis work is to develop and improve the hardware and the firmware designs of a smart device that is developed before as a research prototype. The whole purpose of this thesis work is to acquire the necessary parameters, such as voltage, current, temperature, etc. in order to calculate an accurate estimation of SoC (State of Charge) and SoH (State of Health) and send them to a smart central device through Bluetooth using BLE (Bluetooth Low Energy) protocol.