Battery Equalizers: Why Are They Necessary?

    Battery Equalizers: Why Are They Necessary?

    To extend battery life and prevent premature failure, it is recommended that all battery cells have the same state of charge (SOC) during charge and discharge operations.
    Hence, equalizers are the best option for our batteries to last the useful life expected by the manufacturer, even increasing it by 20-30%.

    The equalizer does nothing more than overload the batteries in a controlled way in order to eliminate possible sulfation that has formed during the time they have been in low-charge conditions.

    What is battery equalization?

    “Equalization is a charging method whose purpose is to restore batteries to their storage capacity, increase efficiency and extend useful life”

    When a battery is in use, the sulfuric acid in the electrolyte reacts chemically with the lead in the plates, producing electricity and lead sulfate. On the other hand, when a battery is being charged, the reverse chemical reaction occurs, where the sulfate is released from the plate and returns to the water forming sulfuric acid, while on the plate we will obtain lead again.

    However, with each charge and discharge cycle, a small amount of sulfate remains attached to the plates. During each loading and unloading, the adhering sulfate will increase.
    If lead sulfate remains on the plates for long periods of time, it will harden and crystallize, consequently reducing the capacity of the battery and making it impossible to deliver an adequate amount of power to its terminals.

    Another effect that occurs over time is that the electrolyte (the mixture of water and sulfuric acid) tends to stratify, dividing into layers. This effect causes the cell, and consequently the battery, to not work uniformly, so its capacity and efficiency are also reduced.

    Effects of overload/discharge and equalization charge

    It stresses the cells and produces excessive gasification, requiring distilled water to be replaced more often.

    [Low charge and over discharge]
    They produce increased sulfation which reduces battery life and reduces cell capacity due to the self-discharge effect.

    – As an example we will use a 12V battery. Therefore, for a 12V solar battery with 6 2V cells in series we would have:

    cellular overload

    Cell number 6 has reached its full charge value of 2,4 V and charging of this cell should stop. But the full voltage of the battery has not reached the absorption level of 14,4V, so the charger will continue to charge the battery until it reaches that value.

    cell over discharge

    When a cell reaches the discharge voltage of 1,9V, the discharge should stop; however, solar inverters and regulators that protect the battery from over-discharge will cut off consumer output once the battery voltage of 11,4V is reached.

    When the battery voltage drops to 11,4V, the cell with the lowest voltage, number 1, will overdischarge with a value of 1,73V while the other cells have not yet reached the critical level of 1,9V .

    equalization load

    During these charges, the battery voltage rises to around 15V, which aids in lead sulfate recombination and equalizes the cell voltage. The equalization process charges at a voltage high enough to ensure overcharging of all the cells that make up the battery.

    In summary, to reset and equalize the voltage of the cells that make up a battery and to recombine the sulfate produced during discharges, it is necessary to perform periodic equalization charges.

    When to perform an equalization?

    There is no rule that governs it, but equalization loads are recommended:

    – For new batteries 1 time every 50 days

    – For very old batteries it can even reach 1 per week.

    – Equalization charges are necessary after deep discharges and charging


    Our equalizers They are specially designed so that once they are connected to the batteries they will NOT be disconnected. This maximizes efficiency since it works continuously with the batteries.

    If you have any questions, do not hesitate to contact contact us, we will be happy to answer your questions and help you with whatever is necessary.

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