5 Battery Types Explained - Sealed, AGM, Gel

With all the different kinds of batteries on the market, it can be difficult to choose the right type for your application. We recommend that you take a few moments to find out more about the 5 most common types of batteries.

1. Flooded Batteries

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.

For this type of battery the typical absorption voltage range 14.4 to 14.9 volts; typical float voltage range 13.1 to 13.4 volts.

Flooded batteries are common and found in many applications, such as automotive starting batteries, motorcycle batteries, ATV batteries, golf carts batteries, and flooded batteries for solar and emergency backup systems.

2. Sealed Batteries

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 in 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 starting and limited starting/deep cycle applications.

For this type of battery the typical absorption voltage range 14.2 to 14.7 volts; typical float voltage range 13.1 to 13.4 volts.

3. VRLA Batteries

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.

For this type of battery the typical absorption voltage range 14.2 to 14.5 volts; typical float voltage range 13.2 to 13.5 volts.

VRLA batteries are common and found in many applications, such as medical mobility scooters batteries and toy and alarm batteries.

4. AGM Batteries 

The Absorbed Glass Mat 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 batteries.

For this type of battery the typical absorption voltage range 14.4 to 15.0 volts; typical float voltage range 13.2 to 13.8 volts.

AGM batteries are common and found in many applications such as RV batteries, boat batteries, motorcycle batteries, ATV batteries, and UPS & Telecom batteries for generators.

5. GEL Batteries

The Gel Cell Battery is similar to the AGM battery 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 battery 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. Battery chargers with gel profile will have information either on the unit, or in the manual, about gel compatibility.

For this type of battery the 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. Lean more about differences between gel cell vs an AGM battery.

Gel batteries are not as common as AGM batteries, but are often found in deep discharge situations such as wheelchair and medical mobility batteries, trolling motor batteries, and RV deep cycle batteries.

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