Paper Title
Design and Implementation of Battery Life Level Indicator

Abstract
Accurate state-of-charge (SOC) estimation is critical for the efficient operation of electric vehicles (EVs) powered by Lithium Iron Phosphate (LiFePO₄) batteries. These batteries, widely used in EVs due to their long cycle life and safety, present challenges for SOC estimation due to their flat discharge voltage profile. This research proposes a battery life indicator that combines voltage monitoring with coulomb counting to improve SOC accuracy. The system was tested on LiFePO₄ batteries used in EV applications, and results demonstrated that the hybrid method significantly enhances SOC estimation accuracy compared to voltage-only methods. The improved SOC estimation ensures more reliable range predictions, optimized battery use, and increased safety for electric vehicles. Keywords - State-of-Charge (SOC), Lithium Iron Phosphate (LiFePO₄), Electric Vehicles (EVs), Battery Life Indicator, Coulomb Counting, Voltage Monitoring, Hybrid SOC Estimation, Battery Management System, Discharge Voltage Profile, Charging Characteristics, Discharging Characteristics