Quick Answer
Active balancing is suitable for high-capacity battery systems, reducing equalization time and extending battery lifespan, while passive balancing is more cost-effective for smaller systems, but requires more frequent equalization.
Choosing Between Active and Passive Balancing
Active balancing involves using an external controller to transfer energy between batteries, maintaining a consistent state of charge and reducing equalization time. This method is ideal for high-capacity systems, typically above 20 kWh, where the cost of the balancing system is offset by the savings in equalization time and extended battery lifespan. For example, if you have a 50 kWh system, active balancing can reduce equalization time from 12 hours to just 1 hour.
Passive Balancing for Smaller Systems
Passive balancing, also known as equalization, involves connecting batteries in series or parallel and allowing them to equalize through the natural flow of current. This method is more suitable for smaller systems, typically below 10 kWh, where the cost of the balancing system is not justified. To minimize the need for frequent equalization, it’s recommended to use high-quality batteries with built-in equalization capabilities, such as lithium-ion batteries with a built-in BMS (Battery Management System).
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