Flooded, Gel and AGM battery types

What is a flooded battery?

A flooded battery is a lead-acid electric storage battery with excess electrolytes (water and sulfuric acid) flooding the battery's individual cells. The fluid levels must be maintained above the plates and connectors to avoid premature failure.

Flooded or wet batteries:

• It can have either sealed manifold venting or accessible venting designs.
• Can use high-antimony, low-antimony or calcium-lead metal grid alloys or a combination of calcium and low-antimony grids (hybrid).
• Use various grid thicknesses relative to application needs and cost requirements.
• Thin grid + low active material ratios and low material density - used in general-purpose starting applications. More plates mean more cold-cranking performance.
• Thicker grids + higher active material ratios with increasing material densities are used in Enhanced Flooded Batteries (EFB) for micro-cyclic Start-Stop vehicles and other emerging specialty transportation requirements. Also, in general-purpose Marine/RV high-cycle applications.
• Thick grid + high active material ratios and high material density, used in purpose-built semi-traction industrial and commercial deep-cycle and long-life renewable energy use.
• Require rigorous levels of maintenance depending upon use.
• Their entire electrolyte volume is free to move within the cell with nothing to prevent the escape of hydrogen and oxygen gases normally lost during charging and discharging (particularly in deep-cycle applications).
• Have excess electrolytes which allows the plates to be completely and even over-discharged while delivering the batteries usable power.
• Have escaping gases in the discharge/charge cycle that can be detrimental to users, sensitive electronic equipment and the environment due to its corrosive nature.
• They are spillable and can only be installed in an upright position. This includes sealed maintenance-free versions of the flooded battery type.
• Are classified as Hazardous.
• Need to utilize equalization charging as a countermeasure against acid stratification.

What is an AGM battery?

• An AGM battery is a lead-acid electric storage battery with the electrolyte (acid) immobilized and absorbed into a woven glass fibre sponge-like material called an Absorbed Glass Mat (AGM).
• Uses various grid thicknesses relative to application and cost requirements.
• Uses various Positive and Negative Active Material amounts and densities depending upon the application's needs.
• Thin grid + low active material ratio & low active material density used in general purpose starting/float and light duty cyclic use.
• Thick grid + high active material ratio & high active material density used in purpose-built Semi-Traction Industrial and General-Purpose Deep-cycle.
• It is sealed using special valve-regulated pressure valves and should never be opened.
• Quality AGM models use individual cell valves with built-in flame arrestors - IMPORTANT.
• Typically uses Lead Calcium-tin metal alloy grids.
• It is maintenance-free with proper charging controls.
• Its entire electrolyte is absorbed in separators, consisting of a sponge-like mass of woven glass fibre material.
• Acid-to-active material ratios and acid-specific gravities may vary according to application and market costing requirements. *** User/integrator should note and verify.
• It uses a recombination reaction to prevent the escape of hydrogen and oxygen gases typically lost in a flooded lead-acid battery (particularly in any cycling applications).
• Is nonspillable.
• It is better than GEL for high-vibration applications because of the cell compression provided by the absorbed glass mat.
• It is better than GEL for high-rate discharge applications because of its lower internal resistance.
• It is better than GEL in low-temperature performance.
• It is generally compatible with vehicle alternator voltages.
• It does not suffer as greatly from acid stratification compared to flooded battery technology because AGM technology completely absorbs and constrains the acid in a fibre separator making it more difficult for the acid to diffuse from the water to accumulate at the bottom of the battery’s cells. This restrained diffusion has been proven to slow the stratifying effect of gravity on battery acid in AGM battery technology. Acid Stratification is the #1 killer of flooded lead-acid batteries. *** Available amounts of usable amp hours CAN BE ADJUSTED BY AS MUCH AS 30% by adjusting the acid and active material densities. Buyers should be aware that increasing acid-specific gravities and acid-to-active material ratios will severely reduce the battery life cycle expectancy and increase usable power per discharge cycle. For example, a 75-amp hour battery can deliver 100 amp hours by increasing the acid-to-active material ratio and the specific gravity of the acid. Both of these adjustments will severely reduce the life of the battery. Therefore, if you are quoted an unbelievable price on a 100AH battery given the current market pricing, you may now know why!

What is a Gel battery?

• A GEL battery is a lead-acid electric storage device that has the electrolyte (acid) immobilized by adding a silica additive that converts the electrolyte into a GEL-like material or consistency.
• Gel technology is a mature technology that has been used since the early 1950s.
• Uses various grid thicknesses relative to application and cost requirements.
• Uses various Positive and Negative Active Material amounts and densities depending upon the application's needs.
• Thin grid + low active material ratios & low material density - used in general purpose float and light duty high cyclic use.
• Thick grid + high active material ratios & high material density - used in purpose-built Semi-Traction Industrial Deep-cycle and Long-Life Renewable Energy.
• It is sealed using special valve-regulated pressure valves and should never be opened.
• Typically uses Lead Calcium-tin metal alloy grids.
• It is maintenance-free with proper charge controls.
• Acid-to-active material ratios and acid-specific gravities may vary according to application and market costing requirements. *** User/integrator should note and verify.
• It uses a recombination reaction to prevent the escape of hydrogen and oxygen gases typically lost in a flooded lead-acid battery (particularly in deep-cycle applications).
• Is nonspillable.
• It is better than AGM in high-heat environments because of the thermal consistency of the GEL within the battery cell.
• It does not suffer as greatly from acid stratification compared to flooded battery technology because GEL technology completely absorbs and constrains the acid in a silicate GEL state, making it more difficult for the acid to diffuse from the water to accumulate at the bottom of the battery’s cells. This restrained diffusion has been proven to slow the stratifying effect of gravity on battery acid in GEL battery technology. Acid Stratification is the #1 killer of lead-acid batteries.