Stationary batteries are almost exclusively lead acid and some maintenance is required[1]https://batteryuniversity.com/learn/article/equalizing_charge,one of which is equalizing charge. Applying a periodic equalizing charge brings all cells to similar levels by increasing the voltage to 2.50V/cell, or 10 percent higher than the recommended charge voltage.
An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that build up on the plates over time. Left unchecked, sulfation can reduce the overall capacity of the battery and render the battery unserviceable in extreme cases. An equalizing charge also reverses acid stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.
According to NorthEastBattery[2]https://northeastbattery.com/equalizing-charges/, for a 12 volt battery, you should charge it with a minimum voltage of 14.4 volts every 10 discharge cycles for at least one hour. This typically averages out to once per month. There are some manufacturers that suggest the equalization charge needs to only be carried out twice a year or as necessary.
According to USABattery[3]https://www.usbattery.com/how-to-equalize-charge-and-prevent-stratification-on-deep-cycle-batteries/, the method used to properly equalize batteries is as easy as using a high-quality battery charger that features an automatic equalizing mode, or has the capability to extend or restart the charging process as needed. Follow these procedures to properly equalize charge your batteries.
- Make sure the Battery is a flooded lead-acid type.
- All electrical loads to the battery nust be removed.
- Connect your charger and charge the batteries until the charger terminates a normal charge cycle.
a.) If the charger is equipped with an automatic equalizing mode, make sure the charger is
connected and powered up long enough to complete equalization.
b.) If the charger is not equipped with an automatic equalization mode, assure the charger
completes a full, automatic charge, and then restart the charger by disconnecting AC
power and reconnecting. The charger should restart and extend the charge time by 1-3
hours.
4. Correct Equalizing Will Cause Gassing And Bubbling Of The Electrolyte.
5. Take Specific Gravity Readings Every Hour.
6. You Will Know That The Equalization Process Is Complete: When the specific
gravity values no longer increase during the gassing stage. If the charger terminates the
charge automatically, before the hourly specific gravity readings are constant, restart the
charger and continue the process until specific gravity readings are constant.
7. Make Sure To Replace Any Water Lost During The Process.