The sulfuric acid electrolyte in these batteries is simply a liquid that covers the plates.
Types of Flooded Wet Cell Batteries
This type of lead acid battery comes in two different configurations
Serviceable – This means that caps can be removed that allow access to the electrolyte. This access allows for specific gravity measurements and for checking and refilling the cells with distilled water.
Maintenance Free – There is no access to the electrolyte in this type of flooded cell battery, thus you may not use a hydrometer to make specific gravity measurements or refill any lost electrolyte.
The flooded wet cell is primarily manufactured for two purposes:
Starting, Lighting and Ignition Battery
Also known an SLI, this type of battery safely provides a great deal of fast energy. This ability to provide high bursts of energy make these batteries ideal for starting engines.
The plates compromising the anode and the cathode are thin and have a great deal of surface area. It is this surface area that allows for the high current demand that is necessary to start a car motor. The issue with respect to these batteries is that they do not allow for regular deep discharges. In fact, regular deep discharges will destroy an SLI battery.
In most cases this is not a problem as the SLI is usually installed into a system that uses the battery energy to start a vehicle and when started, the vehicle alternator carries the electrical load while also recharging the battery.
Deep Cycle Battery
This battery is designed so that it can be charged and discharged more frequently than an SLI battery. This increased cycle life is accomplished by building thicker plates for the anode and cathode. These thicker plates however, reduce the surface area and therefore may not deliver the current necessary to start an engine.
Hybrid Starting and Deep Cycle Battery
As the name implies, the anode and cathode plate thickness is such that it finds a happen medium between the thinness of the SLI plates and the thicker deep cycle plates.