Cylindrical lithium-ion battery cells are a type of rechargeable battery commonly used in a wide range of electronic devices, electric vehicles, and energy storage systems. They are characterized by their cylindrical shape, standardized sizes, and high energy density, making them versatile and. When choosing a lithium battery for your RV, marine vessel, or off-grid application, it's critical to understand the three main cell formats. Each cell type brings unique advantages and challenges. Industries such as electric vehicles and consumer electronics widely adopt these. This paper investigates 19 Li-ion cylindrical battery cells from four cell manufacturers in four formats (18650, 20700, 21700, and 4680).