Today’s electronic devices have higher mobility and are greener than ever before. Battery advancements are fueling this progression in a wide range of products from portable power tools to plug-in hybrid electric vehicles and wireless speakers. In recent years, the efficiency of a battery in terms of how much power it can output with respect to size and weight has dramatically improved. This ongoing transformation of battery technology has prompted many newcomers to learn about designing battery management systems (BMS). Creating a BMS and charging scheme that optimizes battery life requires careful consideration. This paper provides a beginner’s guide to the BMS architecture, discusses the major functional blocks, and explains the importance of each block to the BMS.