A 24V, 36V, or 48V lithium battery system is typically made up of multiple individual cells or battery units connected in series. Over time, the state of charge or voltage of these individual units can drift apart due to differences in internal resistance, capacity, temperature, self-discharge rates, and other factors. This could lead to some cells becoming overcharged or over-discharged, which can reduce the overall performance and lifespan of the battery system.

Therefore, these battery systems often benefit from the use of a battery equalizer or balancer, which is usually part of a Battery Management System (BMS). The equalizer ensures that each individual cell or unit within the system is at the same state of charge or voltage, thereby maximizing the battery system's capacity and prolonging its lifespan.

However, the specific need for a battery equalizer or balancer can depend on various factors, including the specific type of lithium battery (e.g., LiFePO4, Li-ion, etc.), the quality and uniformity of the individual cells or units, the application, and the charge/discharge patterns.