NewMar London Aire 2021, Owner'S Manual

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71
ELECTRICAL
Life Span Of A Battery
Not long ago, motor homes only used a single 12 Volt
house battery. Today, however, it is standard to have at
least two batteries, and up to 16 total in some Newmar
coaches, powering inverters up to 3000 watts. As energy
requirements increase, the average battery life decreases.
The life span of a deep cycle battery will vary considerably
with how it is used, how it is maintained and charged,
temperature, and other factors. The life span is dependent
upon usage but often ranges between six months to 48
months. Only 30 percent of all batteries actually reach the
48 month mark.
It is best practice to change the complete battery bank
when a new battery becomes necessary, as the battery
bank is only as good as the weakest cell. One simple way
to extend battery life is to hook it up to a solar charger
during the o ff months.
Common Battery Terms
Ampere (Amp) - A unit that defines the flow rate of
electricity (current) in a circuit.
Amp Hour (AH) - Measurement of electrical storage
capacity on a deep cycle battery. The standard amp rating
is taken for 20 hours. Example: A 100 AH rated battery is
determined like this: Draw from the battery for 20 hours
provides a total of 100 amp hours, translating to about five
amps an hour (5 amps x 20 hours = 100 AH). However, it is
important to know that the total time of discharge and load
applied is not a linear relationship. As your load increases,
your realized capacity decreases. This means if you
discharged that same 100 AH battery by a 100 amp load, it
will not give you one hour of runtime. On the contrary, the
perceived capacity of the battery will be about 64 AH.
Cold Cranking Amps (CCA) -Measures the number
of amps a battery can deliver at 0° F for 30 seconds
without dropping below 7.2 Volts (1.2 Volts per cell). A
high CCA battery rating is especially important in engine-
starting battery applications and in cold weather. This
measurement is not particularly important in deep cycle
batteries, though it is the most commonly known battery
measurement.
Cranking Amps (CA) - Measures available current at 32° F
and is also called marine cranking amps (MCA).
Depth of Discharge (DOD) - Measures the percent of
rated capacity to which a cell or battery is discharged. It
is the reciprocal of a battery’s state of charge. Example: A
battery that has a depth of discharge of 45 percent has a
state of charge of 55 percent.
Reserve Capacity (RC) - Measures the number of minutes
a fully charged battery can continuously deliver 25 amps
at 80 ° F before the voltage drops below 10.5 Volts. This
measurement represents the amount of time the battery
can operate if a charging system failure occurs.
Electrolyte Specific Gravity (battery test) - Unit of
measure which compares the weight of the electrolyte
solution to the weight of water. This test is performed
with a hydometer or a refractometer that is made for
testing batteries. This type of test is used to determine
the battery’s state of charge; however, it cannot be used
on sealed batteries.
Battery Types
LIQUID LEAD ACID / FLOODED
The Lead Acid battery consists of a plastic container with
cells molded into it. Each cell contains plates, lead, and
lead oxide (various other elements are used to change
density, hardness, porosity, etc.) with 35 percent sulfuric
acid and a 65 percent water solution. This solution is
called an electrolyte, which causes a chemical reaction
that releases electrons.
When testing a battery with a hydrometer, the amount of
sulfuric acid in the electrolyte is measured. If the reading
is low, the chemistry that makes electrons is lacking. The
sulfur is now resting on the battery plates and will remain
there until the battery is recharged and the sulfur returns
to the electrolyte.
ABSORBED GLASS MAT (AGM) / DRY
CELL
The Absorbed Glass Mat battery is just like a flooded
battery, except the electricity is maintained in the glass
mats, as opposed to freely flooding the plates. Very
thin fibers are woven into a mat to increase the surface
area to hold su ffi cient electrolyte on the cells for their
lifetime. The construction allows the electrolyte to remain
suspended in close proximity with the plate’s active
material, enhancing both the discharge and recharge
e ffi ciency.
When Deep Cycle AGM batteries are not discharged more
than 60 percent, the cycle life could be approximately
a few hundred cycles. If you do not use or operate your
equipment daily, AGM batteries will hold their charge
better than most other types. In most cases AGM batteries
will provide a greater life span and cycle life than a Wet
Cell battery.
AGM batteries are also often referred to as Sealed
Regulated Valve, Dry Cell, Non-Spillable, and Valve-
Regulated Lead Acid batteries.
CAUTION
!
Use only distilled water to fill flooded / liquid lead
acid batteries.
CAUTION
!
Follow battery manufacturer instructions. Do not add
any liquid to AGM batteries.
GEL CELL BATTERIES
The Gel Cell is similar to the AGM battery because the
electrolyte is suspended; however, 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 (gel) or sti ff en.
The recharge voltage on this type of cell is lower than the
other types of lead acid batteries, due to the likelihood
of an adverse reaction to over-voltage charging. Gel Cell
batteries are best used in very deep cycle applications
and may last longer in hot weather applications.