Equalizing and Balance Charging

Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. We recommend equalizing when low or wide ranging specific gravity (± .015) is detected after fully charging a battery.

Equalizing is an “over voltage - overcharge” performed on flooded lead acid batteries after they have been fully charged. It helps to eliminate stratification – the uneven distribution of acid - and sulfation – the build up of sulfate crystals on the plates. These are two of many conditions that can reduce the overall performance and life of a flooded battery. An Equalize charge – or equalizing – should only be used on flooded batteries when specific gravity readings vary from cell to cell at +/-.015 on a fully charged battery.

Step by Step Equalizing

• Verify the battery(s) are flooded type.
• Check and water cells if needed.
• Remove all loads from the batteries.
• Connect battery charger.
• Set charger to equalizing mode.
• Start charging batteries.
• Batteries will begin gassing and bubbling vigorously.
• Take specific gravity readings every hour.
• Equalization is complete when specific gravity values no longer rise during the gassing stage.

Equalize charging should not be performed on standard AGM or Gel batteries.

“Balance Charge” stages are recommended by Discover and other high quality manufacturers of AGM and Gel Traction technology. Balance charge curves are included in all Discover Charger recommendations. Balance Charging is similar to an equalize charge cycle but is performed at a lower voltage and finishing current.

NOTE: Many chargers do not have an equalization setting so this procedure can’t be carried out.