Characteristics of Battery Types
This is the traditional engine start, tractor and deep cycle style battery. The liquid electrolyte is free to move in the cell compartment. The user has access to the individual cells and can add distilled water as the battery dries out. Popular uses are engine starting and deep cycle designs.
Typical absorption voltage range 14.4 to 14.9 volts, typical float voltage range 13.1 to 13.4 volts.
Sealed:
This term can refer to a number of different constructions, including only a slight modification to the flooded style. In that case, even though the user does not have access to the cell compartments, the internal structure is still basically the same as a flooded battery. The only difference is that the manufacturer has ensured that a sufficient amount of acid is the battery to sustain the chemical reaction under normal use throughout the battery warranty period. Other types of lead acid batteries are also sealed, as explained below. Very popular uses are engine start and limited starting/deep cycle applications.
Typical absorption voltage range 14.2 to 14.7 volts, typical float voltage range 13.1 to 13.4 volts.
VRLA:
This stands for Valve Regulated Lead Acid battery. This is also a sealed battery. The valve regulating mechanism allows for a safe escape of hydrogen and oxygen gasses during charging.
Typical absorption voltage range 14.2 to 14.5 volts, typical float voltage range 13.2 to 13.5 volts.
AGM:
The Absorbed Glass Matt construction allows the electrolyte to be suspended in close proximity with the plates active material. In theory, this enhances both the discharge and recharge efficiency. Actually, the AGM batteries are a variant of Sealed VRLA batteries, just a more advanced design. Popular usage includes high performance engine starting, power sports, deep cycle, solar and storage battery.
Typical absorption voltage range 14.4 to 15.0 volts, typical float voltage range 13.2 to 13.8 volts.
GEL:
The Gel cell is similar to the AGM style because the electrolyte is suspended, but different because technically the AGM battery is still considered to be a wet cell. The electrolyte in a GEL cell has a silica additive that causes it to set up or stiffen. The recharge voltages on this type of cell are lower than the other styles of lead acid battery. This is probably the most sensitive cell in terms of adverse reactions to over-voltage charging. Gel Batteries are best used in VERY DEEP cycle application and may last a bit longer in hot weather applications. If the incorrect battery charger is used on a Gel Cell battery poor performance and premature failure is certain.
Typical absorption voltage range 14.0 to 14.2 volts, typical float voltage range 13.1 to 13.3 volts.
Note about Gel Batteries: It is very common for individuals to use the term GEL Cell when referring to sealed, maintenance free batteries, much like one would use Kleenex when referring to facial tissue or "Xerox machine" when referring to a copy machine. Be very careful when specifying a charger. More often than not, what someone thinks to be a Gel Cell is really a sealed, maintenance free, VRLA or AGM style battery.
