Owner`s manual

6
Chapter 4
Your boat uses 12 volt DC electricity otherwise known
as direct current. It is called DC because it fl ows only
one way in a circuit. Specifi cally helm gauges, batteries,
battery cables, engine electrical components, engine wiring
harnesses, dash switches, selected lighting, shower sump,
bilge pumps, and vacuum toilets are all components using
a 12 volt DC system.
In the DC system used in the United States the red wire
is designated as the “hot” or conductor wire and the
black wire is referred to as the ground wire. At times
other current carrying wires are color coded such as blue
to identify their use as a low voltage conductor. This is
especially helpful in troubleshooting and adding additional
equipment. Be sure to review the wiring schematics in the
drawing section of the technical chapter.
Direct current is stored in the vessel’s batteries and produced
through the engine alternators while the engines are
running or by the battery charger at dockside.
The alternators charge the batteries by sending current
through the main distribution panel relays, battery switches
and harnesses to the appropriate battery. Normal DC
voltage is between 12 and 15 volts. Lower or higher
readings could indicate a charging malfunction or a weak
battery.
The engine alternators used on your vessel are internally
self “excited” and produce DC current at idle.
Current specifi cations for Volvo alternator output is 115
amps. The IPS steering system needs additional operating
current and this is one reason the alternator output is
higher than conventional units.
DIRECT CURRENT (12 VOLTS)
BATTERY (12 VOLTS) DESCRIPTION
On board direct current is stored in the ship’s “wet cell”
batteries. There are 2 engine starting batteries and a deep
cycle “house” battery.
BATTERY SPECIFICATIONS
Battery
Type
Group
CCA @32
Degrees F.
Reserve
Capacity
Engine
Cranking
31A 1260 195 min.
House 8D 1700 430 min.
BATTERY TERMINOLOGY
Group- Batteries are divided into groups which identify
the height, length, and width of the battery. This is useful
information should a replacement battery become neces-
sary.
Cold Cranking Amps (CCA)- This rating measures the
cranking power a full charged marine battery has available
to start at 32 degrees F. Basically, the higher the rating the
greater starting power of the battery.
Reserve Capacity (RC)- As usage on the boat increases
so does the need for more reserve capacity. The reserve
capacity represents the length of time in minutes a new
fully charged battery can maintain the yacht’s electrical
needs without the engine running or in the event the al-
ternator fails.
TYPICAL
ENGINE
STARTING
BATTERY
TYPICAL
HOUSE
BATTERY
BATTERY
BOOT
REMOVE
CAP
REMOVE
CAP