Charging Gel and AGM batteries

Charging batteries properly requires administering the correct current at the proper voltage. The original instructions for your charging equipment should be referenced for proper charging. Here is a list of helpful items to remember when charging.

  1. Become familiar with and follow the instructions issued by the charger manufacturer.
  2. Batteries should be charged after each period of use.
  3. Lead-acid batteries do not develop a memory and do not need to be fully discharged before recharging.
  4. Charge flooded batteries only in well-ventilated areas. Keep sparks away from charging or recently charged batteries.
  5. Verify charger voltage settings are correct for the type of battery you are charging (Flooded, AGM or GEL).
  6. Correct the charging voltage to compensate for temperatures above and below 25°C/77°F.


Compensation for battery temperature above or below 25°C/77°F

  • Subtracting 0.005 volts per cell for each 1°C (0.003 volts per 1°F) above 25°C or,
  • adding 0.005 volts per cell for each 1°C (0.003 volts per 1°F) below 25°C
  1. Check the water level on flooded batteries before and after charging (see the Watering section).
  2. Tighten all vent caps on flooded batteries before charging.
  3. Prevent overcharging the batteries. Overcharging causes excessive gassing (water breakdown), heat buildup, and battery aging in flooded batteries and will dry out the electrolyte and damage VRLA DRY CELL AGM and GEL batteries.
  4. Prevent undercharging the batteries. Undercharging causes acid stratification in wet flooded batteries.
  5. Do not charge a frozen battery; allow it to thaw at room temperature.
  6. Avoid charging at temperatures above 50C/125F if possible.

Charging batteries

Charging batteries properly requires administering the correct current at the proper voltage. The original instructions for your charging equipment should be referenced for proper charging. Here is a list of helpful items to remember when charging.

Become familiar with and follow the instructions issued by the charger manufacturer.

  1. Batteries should be charged after each period of use.
  2. Lead-acid batteries do not develop a memory and do not need to be fully discharged before recharging.
  3. Charge flooded batteries only in well-ventilated areas. Keep sparks away from charging or recently charged batteries.
  4. Verify charger voltage settings are correct for the type of battery you are charging (Flooded, AGM or GEL).
  5. Correct the charging voltage to compensate for temperatures above and below 25°C/77°F.


Compensation for battery temperature above or below 25°C/77°F

  • Subtracting 0.005 volts per cell for each 1°C (0.003 volts per 1°F) above 25°C or,
  • adding 0.005 volts per cell for each 1°C (0.003 volts per 1°F) below 25°C
  1. Check the water level on flooded batteries before and after charging (see the Watering section).
  2. Tighten all vent caps on flooded batteries before charging.
  3. Prevent overcharging the batteries. Overcharging causes excessive gassing (water breakdown), heat buildup, and battery aging in flooded batteries and will dry out the electrolyte and damage VRLA DRY CELL AGM and GEL batteries.
  4. Prevent undercharging the batteries. Undercharging causes acid stratification in wet flooded batteries.
  5. Do not charge a frozen battery; allow it to thaw at room temperature.
  6. Avoid charging at temperatures above 50C/125F if possible.

Charging batteries

Charging batteries properly requires administering the correct current at the proper voltage. The original instructions for your charging equipment should be referenced for proper charging. Here is a list of helpful items to remember when charging.

  1. Become familiar with and follow the instructions issued by the charger manufacturer.
  2. Batteries should be charged after each period of use.
  3. Lead-acid batteries do not develop a memory and do not need to be fully discharged before recharging.
  4. Charge flooded batteries only in well-ventilated areas. Keep sparks away from charging or recently charged battery.
  5. Verify charger voltage settings are correct for the type of battery you are charging (Flooded, AGM or GEL).
  6. Correct the charging voltage to compensate for temperatures above and below 25°C/77°F.


Compensation for battery temperature above or below 25°C/77°F

  • Subtracting 0.005 volts per cell for each 1°C (0.003 volts per 1°F) above 25°C or,
  • adding 0.005 volts per cell for each 1°C (0.003 volts per 1°F) below 25°C
  1. Check the water level on flooded batteries before and after charging (see the Watering section).
  2. Tighten all vent caps on flooded batteries before charging.
  3. Prevent overcharging the batteries. Overcharging causes excessive gassing (water breakdown), heat buildup, and battery aging in flooded batteries and will dry out the electrolyte and damage VRLA DRY CELL AGM and GEL batteries.
  4. Prevent undercharging the batteries. Undercharging causes acid stratification in wet flooded batteries.
  5. Do not charge a frozen battery; allow it to thaw at room temperature.
  6. Avoid charging at temperatures above 50C/125F if possible.