Jayco 2009 Melbourne, Owner'S Manual, Page: 49 / 102

SECTION 6
ELECTRICAL SYSTEM - 30 AMP
45
A
UXILIARY
S
TART
S
YSTEM
Your motorhome is equipped with an auxiliary
start switch which can momentarily connect
both the house and chassis batteries should
the chassis battery become discharged. To
operate, depress the "Aux. Start" switch
(located on the front driver’s dash) and hold.
Now, use the ignition key to start the chassis
engine. Release the "Aux. Start" switch after
the engine has started.
H
OUSE
B
ATTERY
Your RV has many 12-volt DC loads. When
combined, their total is more than the
converter can produce. High demands for 12-
volt power can be met by the house battery
for limited periods of time. The 12-volt DC
electrical system is designed for usage with a
Group 27, deep cycle battery. In a
motorhome, the house battery is usually
referred to as the house (or coach) battery.
The house battery is factory-installed to
provide temporary 12-volt power when 120-
volt power is not available to operate the
power converter. When drawing energy from
the battery, remember that there is a limited
amount of power available before the battery
needs to be recharged.
To recharge the house battery
When the engine is running, the alternator will
automatically charge the battery through the
auxiliary start solenoid. When parked at a
campsite, plug into shoreline power. With
minimal or low load on the 12-volt electrical
system, the converter will automatically
charge the battery. This may take several
hours and depends upon battery condition
and the number of 12-volt devices operated
during the charging period.
Dry camping
Consider the charge condition of the house
battery when dry camping. If the house
battery is not being recharged and power is
being drawn from it, it will eventually
discharge. A battery will discharge at a faster
rate as its energy level becomes depleted. It
is recommended you plan your electrical
usage accordingly.
A fully charged 12V battery will read 12.7
volts DC and 1.265 specific gravity at 80°F
(32°C). The house battery is considered
discharged at 11.8 volts DC by electronic
standards. When voltage drops below those
levels, permanent battery damage may occur.
Typically, a deep cycle battery has an amp-
hour rating of 75-100 amps. If you run the
furnace and refrigerator simultaneously, you
will be using approximately (12.0 + 3.0) 15.0
amps per hour. This does not include any 12-
volt lights, water pump or any other 12-volt
component.
If the furnace and refrigerator in the
above example operated constantly, a
75 amp-hour battery would become fully
discharged in 5 hours (75ah / 15a = 5h).
Battery storage instructions
Some equipment in your RV will draw small
amounts of current even when turned OFF.
To prevent house battery discharge when the
RV is not connected to power through the
shoreline power cord, it is recommended you
shut OFF the 12-volt battery disconnect
switch and disconnect the battery negative
cable at the house battery.
During storage, it is important to check battery
voltage at least every two weeks and
recharge as needed. If you remove the
battery from your RV, store them in a dry, cool
area as per the OEM instructions.
Replacement and maintenance
For accuracy, test battery voltage using a volt-
ohm meter (customer supplied
). When it is
time to replace the house battery, replace it
with a Group 27 deep cycle battery only.
Contact the battery OEM for further
information. Do not reverse the positive and
negative battery cables. Doing so will blow the
reverse polarity fuses that protect the
converter.
C
HASSIS
B
ATTERIES
Each OEM chassis is built with batteries to
provide energy to start the engine and
operate devices supplied with the chassis.
The OEM chassis battery is furnished and
warranted by your GM or Ford dealership (as
applicable).