Batteries
are generally misunderstood and almost universally
ignored until they fail. The purpose of all batteries
is to store
chemical energy and to convert this chemical energy
into
electrical energy when the need arises.
There are three types of batteries commonly used in RVs: flooded
lead acid... gel.... nd absorbed glass mat (AGM).
All of these depend on lead acid chemistry. The difference is the
method and the material in which the acid is contained and the grid
or plate material, which is either lead antimony or lead calcium.
The type of battery, the method used to contain the lead acid, and the type of material
used as plates, are basically what determine the battery’s cost.
When a lead-acid battery is discharged, electrolyte and the active material on the plates
of the battery are consumed and produce water and lead sulfate. When a lead-acid battery
is charged, the process is basically reversed.
The application for which the battery is to be used is of critical importance: engine starting
or house batteries. Although many RVs use the same batteries for both, the tasks are very
different and batteries specifically designed for the application should be used Engine
starting is a relatively easy task for a battery and is usually best accomplished by a battery
constructed with many thin plates.
This allows large amounts of current (amps) to flow readily from the starting motor and
are quickly recharged by an engine-driven alternator with a typical automotive type regulator.
House batteries-- the batteries that supply power to your electronics, lighting, pumps and
other appliances in your RV-- are a different matter entirely. These batteries are required to
supply power over long periods of time. For these applications, thick plate “deep-cycle”
batteries are in order.
These batteries are designed to allow deep discharge (up to 50% of rated capacity) and
can be recharged many times.
Although batteries claiming to be “deep-cycles” vary widely, a general rule is that top quality
flooded lead-acid types will give the longest cycle life, followed by AGMs and gels.
Four years is the average life cycle of RV house batteries.
Next month we will discuss charging methods and maintaining your RV batteries.
Enjoy the RV life, and be safe.
