Function of a Battery Equalizer

Answer 1

A battery Equalizer is a device in a battery bank that performs battery equilibration. Typically, the individual cells in a battery have somewhat different capacities and may be at different levels of SOC (state of charge). Without redistribution, discharging must stop when the cell with the lowest capacity is empty (even though other cells are still not empty); this limits the energy that can be taken from and returned to the battery. Without equalizing, the cell of smallest capacity is a "weak point", it can be easily overcharged or over-discharged while cells with higher capacity undergo only partial cycle. For the higher capacity cells to undergo full charge/discharge cycle of the largest amplitude, Equalizer should "protect" the weaker cells; so that in an equalized battery, the cell with the largest capacity can be filled without overcharging any other (i. e. weaker, smaller) cell, and it can be emptied without over-discharging any other cell. Battery equalizing is done by transferring energy from or to individual cells, until the SOC of the cell with the lowest capacity is equal to the battery's SOC. The process maximizes the battery bank capacity to make all of its energy available for use and increase the batteries lifetime.