Daewoo CIELO EURO III, Manual

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ENGINE ELECTRICAL 1E – 3 8
DAEWOO T-154 BL2,3
GENERAL DESCRIPTION
AND SYSTEM OPERATION
BATTERY
The battery has three major functions in the electrical
system. First, the battery provides a source of energy
for cranking the engine. Second, the battery acts as a
voltage stabilizer for the electrical system. Finally, the
battery can, for a limited time, provide energy when the
electrical demand exceeds the output of the generator.
The sealed battery is standard on all cars. There are no
vent plugs in the cover. The battery is completely
sealed, except for two small vent holes in the sides.
These vent holes allow the small amount of gas pro-
duced in the battery to escape.
The sealed battery has the following advantages over
conventional batteries:
D
No water need be added for the life of the battery.
D
It is protected against overcharge. If too much volt-
age is applied to the battery, it will not accept as much
current as a conventional battery. In a conventional
battery, the excess voltage will still try to charge the
battery, leading to gassing, which causes liquid loss.
D
It is not as liable to self-discharge as a conventional
battery. This is particularly important when a battery
is left standing for long periods of time.
D
It has more power available in a lighter and a smaller
case.
RATINGS
A battery has two ratings: (1) A reserve capacity rating
designated at 27
_
C (81
_
F), which is the time a fully
charged battery will provide 25 amperes current flow at
or above 10.5 volts; (2) A cold cranking amp rating de-
termined under testing at -18
_
C (0
_
F), which indicates
the cranking load capacity.
RESERVE CAPACITY
The reserve capacity is the maximum length of time it is
possible to travel at night with the minimum electrical
load and no generator output. Expressed in minutes,
Reserve Capacity (or RC rating) is the time required for
a fully charged battery, at a temperature of 27
_
C (81
_
F)
and being discharged at a current of 25 amperes, to
reach a terminal voltage of 10.5 volts.
COLD CRANKING AMPERAGE
The cold cranking amperage test is expressed at a bat-
tery temperature of -18
_
C (0
_
F). The current rating is
the minimum amperage, which must be maintained by
the battery for 30 seconds at the specified temperature,
while meeting a minimum voltage requirement of
7.2 volts. This rating is a measure of cold cranking ca-
pacity.
The battery is not designed to last indefinitely. However,
with proper care, the battery will provide many years of
service.
If the battery tests well, but fails to perform satisfactorily
in service for no apparent reason, the following factors
may point to the cause of the trouble:
D
Vehicle accessories are left on overnight.
D
Slow average driving speeds are used for short peri-
ods.
D
The vehicle’s electrical load is more than the genera-
tor output, particularly with the addition of aftermarket
equipment.
D
There are defects in the charging system, such as
electrical shorts, a slipping generator belt, a faulty
generator, or a faulty voltage regulator.
D
There has been battery abuse, including failure to
keep the battery cable terminals clean and tight, or a
loose battery hold-down.
D
There are mechanical problems in the electrical sys-
tem, such as shorted or pinched wires.
BUILT-IN HYDROMETER
The sealed battery has a built-in, temperature-compen-
sated hydrometer in the top of the battery. This hydrom-
eter is to be used with the following diagnostic
procedure:
1. When observing the hydrometer, make sure that the
battery has a clean top.
2. Under normal operation, two indications can be ob-
served:
D
GREEN DOT VISIBLE – Any green appearance is
interpreted as a “green dot,” meaning the battery is
ready for testing.
D
DARK GREEN DOT IS NOT VISIBLE – If there is
a cranking complaint, the battery should be tested.
The charging and electrical systems should also
be checked at this time.
3. Occasionally, a third condition may appear:
D
CLEAR OR BRIGHT YELLOW – This means the
fluid level is below the bottom of the hydrometer.
This may have been caused by excessive or pro-
longed charging, a broken case, excessive tipping,
or normal battery wear. Finding a battery in this
condition may indicate high charging by a faulty
charging system. Therefore, the charging and the
electrical systems may need to be checked if a
cranking complaint exists. If the cranking com-
plaint is caused by the battery, replace the battery.
CHARGING PROCEDURE
1. Batteries with the green dot showing do not require
charging unless they have just been discharged, such
as in cranking a vehicle.