Diagnosis; Battery - Suzuki Jimny Service Manual

6H-6 CHARGING SYSTEM

Diagnosis

Battery

COMMON CAUSES OF FAILURE
A battery is not designed to last indefinitely; however, with proper
care, it will provide many years of service. If the battery performs
satisfactorily during test but fails to operate properly for no appar-
ent reason, the followings are some factors that may point to the
cause of trouble:
• Accessories left on overnight or for an extended period with-
out the generator operating.
• Slow average driving speeds for short periods.
• Electrical load exceeding generator output particularly with
addition of after market equipment.
• Defects in charging system such as high resistance, slipping
drive belt, loose generator output terminal, faulty generator
or voltage regulator. Refer to "Generator" in this "Diagnosis"
section.
• Battery abuse, including failure to keep battery cable termi-
nals clean and tight or loose battery hold down.
• Mechanical problems in electrical system such as shorted or
pinched wires.
VISUAL INSPECTION
Check for obvious damage, such as cracked or broken case or
cover, that could permit loss of electrolyte. If obvious damage is
noted, replace battery. Determine cause of damage and correct
as needed.
HYDROMETER TEST
The direct method of checking the battery for state of charge is to
carry out a high rate discharge test, which involves a special pre-
cise voltmeter and an expensive instrument used in the service
shops, but not recommendable to the user of the vehicle.
At 20 °C of battery temperature (electrolyte temperature):
• The battery is in FULLY CHARGED STATE if the electrolyte
S.G. is 1.280.
• The battery is in HALF CHARGED STATE if the S.G. is
1.220.
• The battery is in NEARLY DISCHARGED STATE if the S.G.
is 1.150 and is in danger of freezing.
As the S.G. varies with the temperature, if battery temperature is
not at 20 °C (68 °F), you have to correct your S.G. reading (taken
with your hydrometer) to the value at 20 °C (68 °F) and apply the
corrected S.G. value to the three-point guide stated value. For the
manner of correction, refer to the graph showing the relation
between S.G. value and temperature.