Battery Charge Time & Consumption Rate; Lights; Incandescent - Monaco 2009 Knight Owner's Manual

Battery Charge Time & Consumption Rate
Calculating Run Times:
Calculating run time figures when
operating 120 Volt AC electrical items with
an inverter can be exponential due to battery
characteristics. Flow characteristics of
electrons vary with different battery types and
chemical compositions. Deep cycle batteries
are generally designed to slowly release a
majority of their charge capacity. Deep cycle
batteries are rated in amp hours (Ahrs) with the
discharge occurring over an extended period
of time before the battery is charged. Engine
starting batteries are designed to quickly
release large amounts of current for short
durations, without depleting battery reserves.
Commercial type batteries bridge the gap of
deep cycle and engine batteries. Commercial
batteries release medium amounts of current
over a longer period of time but they are not
designed to cycle their charge capacity.
The working range of a deep cycle battery is
between 50 and 100% state of charge (SOC).
Deep cycle batteries should not be cycled
below 50% state of charge. Discharging a
deep cycle battery below 50% state of charge
shortens the life of the battery. Deep cycle
batteries use an amp hour rating which is
usually calculated over a 20 hour discharge
interval. For example: A deep cycle battery
with a rated capacity of 100 Ahrs. is designed
to release current at the rate of 5 Amps per
hour. Multiply a 5 Amp load over a 20 hour
discharge period equals the rated 100 Ahr.
capacity. These discharge figures are calculated
with the battery starting at 100% state of
charge with the battery at 80º F when the
discharge cycle begins. However, increasing
the discharge load applied to the battery from
5 Amps to 10 Amps on a 100 Ahr battery does
not yield ten hours of discharge time. This is
due to the internal reactions which occur when
a battery is discharging. Actual discharge time
for a 10 Amp load may be closer to eight hours
of discharge time. Increasing the load applied
to the battery to 20 Amps will not yield five
hours discharge time but may be less than
three hours. It might be understood as a point
of diminishing return.
Calculating applied loads to an inverter to
approximate run time from the battery amp
hours available is not an equal trade up when
voltage is inverted and amperage is calculated.
When the inverter is used to operate an AC
load it uses approximately ten times the DC
current needed from the battery when inverting
12 Volts DC to operate the 120 Volt AC item.
There is also a small efficiency loss of about
10% when inverting. For example: When
using the inverter to operate an AC electrical
item, which has a current draw rating of 2
Amps, the inverter will use over 20 Amps DC
power from the batteries.
Determining Current Consumption:
First determine the amount of current used
by an AC item. For example: The television is
rated at 200 watts at 120 Volts AC. Calculate
watts to amps. Divide 200 watts by the
operating voltage of 120, this equals 1.6
Amps. Multiply 1.6 Amps AC current by a
factor of ten the inverter will use, this equals
16 Amps DC battery current. Add the revised
10% efficiency loss figure, this calculates to
a total of 17.6 Amps DC. If the battery bank
capacity is rated at 500 Ahrs., actual elapsed
time to the suggested 50% state of charge
would net viewing time for the television at
approximately 13 hours in ideal conditions.
The run time figure will vary greatly with
the actual state of charge of the battery bank
when the discharge process begins. Ambient
temperature, combined with other working
loads, such as lights and parasitic loads applied
to batteries, affect run times. Calculating the
exact run time is not precise due to all the
variables and equations involved; however,
an approximate time figure can be obtained.
Proper battery maintenance and charge cycles
affect battery performance. Observe the
battery condition with hydrometer and voltage
readings. Use only distilled water when filling
batteries. To achieve the highest quality of
battery performance and longevity maintain
the batteries in their proper operating range.

LIgHTS

Light fixtures found in the motorhome vary
greatly depending on floor plans. The articles
that follow reflect a general overview of some
of the more common fixture types. Actual
styles and types may differ.

Incandescent

The bulb inside the 12V incandescent light is
replaceable.
To Replace a Bulb:
Carefully squeeze the lens cover then

gently pull the cover out. The cover has
tabs that lock the cover in place
Using a clean cloth or piece of tissue

carefully grasp the bulb and rotate to the
unlock position.
Remove bulb from the socket.

The bulb replacement is 1141 12V 21CP.

1