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Electrical system
Electrical installation
General
The electrical installation has to be planned very
carefully and carried out with the utmost care. Seek
simplicity when designing the electrical system.
The wires and connectors used in the installation
have to be of a type approved for marine use. The
wires should be routed in a protective sheath and
clamped properly.
Make sure that the wires are not installed too close to
heated parts of the engine or close to another source
of heat. The wires must not be subject to mechanical
wear. If necessary, route the wires through protective
tubing.
Minimize the number of joints in the system. Make
sure that cables, and joints in particular, are acces-
sible for inspection and repair.
It is recommended to supply a wiring diagram of the
complete electrical system with the boat. This will
simplify fault tracing and installation of additional
equipment considerably.
NOTE! Make sure that no joints in the engine room
are placed deep down. All cable joints should be lo-
cated higher up than the alternator.
Batteries
Battery terminology
Capacity
Capacity is measured in Ampère-hours (Ah). The
starter battery capacity (Ah) is usually stated as the
20 hour capacity of the battery, i.e. the battery can
be discharged at a constant current for 20 hours to a
final voltage of .75 V/cell. For example: If a battery
can produce 3 A for 20 hours, its capacity is 60 Ah.
The cold cranking amperage (CCA) measures the
starting performance of the battery. The society of
Automotive Engineers (SAE) has specified the fol-
lowing test: A battery at a temperature of –8° C
(0°F) must be able to deliver a current equal to the
cold cranking amps for 30 seconds with the voltage
remaining above.2 V/cell or 7.2 V for a 2 V battery.
There are other CCA tests defined by DIN, IEC, EN
etc. These tests will give different CCA values com-
pared with the SAE test.
Battery capacity is affected by temperature. Battery
capacity is specified at +20°C (68°F). Cold consider-
ably reduces a battery’s ability to release its energy.
The following table shows the difference in capacity
b20°C (68°F) and -8°C (0°F).
Temperature +20°C (68°F)
-8°C (0°F)
Capacity
00%
50%
70%
35%
40%
25%
Содержание D11 series
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