This whitepaper discusses the critical role of Battery Management Systems (BMS) in managing the charging, discharging, and safety of modern battery packs. It highlights the importance of BMS in protecting batteries, particularly lithium-ion and LiFePO4, from damage due to overcharging, undercharging, and overheating. The paper outlines key design considerations, including power level circuitry and signal line driver segments, and emphasizes the role of transformers in providing necessary isolation and meeting safety standards.