Capacitance Principle: : No external power supply is required,The working principle is Capacitor fit transfers the charge transporter, use the internal energy transfer of the battery to transfer and balance the entire battery pack.the equalization board can be connected to the battery to start the equalization work.Product Information: : Protective Case needs to be assembled by yourself,After the assembly is completed, tear off the outer yellow film.Before connecting the equalization board, check whether each piece of wiring is correct, insulation between the bottom board and the battery connection terminals is required to prevent burnout.Model:3S-4S Suitable : Lithium Iron Phosphate, NCM Ternary Polymer,(Not Fit Lithium Titanate).Original Design: :using the original ultra-low internal resistance MOS, 2OZ copper thickness PCB, equalizing current 0-5.5A, The more balanced the battery, the lower the current.Voltage is 1.8 V-4.5V ,Suggest Battery Capacity: 60-300AH.Protection switch: : With sleep protection, when the voltage is lower than 3V, it will automatically stop and enter the sleep state to reduce the damage to the battery.With a protective case, it can better protect 3S 4S 5A Active Equalizer and Extend product life.Satisfactory service: :Protective Case needs to be assembled by yourself, We Provide 24-hour online service,If you encounter any problems, Please email SELLER SUPPORT (Not support), we will give you a perfect solution.