Komatsu 830E-AC, Shop Manual

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D10-6 Battery Charging Alternator D10003 07/06
Troubleshooting
The two most common problems that occur in the
charging system are undercharging and overcharg-
ing of the truck's batteries.
Undercharging
An undercharged battery is incapable of providing
sufficient power to the truck's electrical system.
Some possible causes for an undercharged battery
are:
Sulfated battery plates
Loose or corroded battery connections
Defective wire in the electrical system
Loose alternator drive belt
Defective alternator or regulator
Defective battery equalizer
Overcharging
Overcharging, which causes battery overheating, is
first indicated by excessive use of water. If allowed to
continue, the cell covers will push up at the positive
ends of the battery case. In extreme situations, the
battery container will become distorted and cracked.
Leakage can be detected by continual wetness of the
battery or excessive corrosion of the terminals, bat-
tery carrier, and surrounding area. A slight amount of
corrosion is normal in lead-acid batteries. Inspect the
case, covers, and sealing compound for holes,
cracks, or other signs of damage. Check the battery
hold-down connections to ensure they are not over-
tightened, which could cause a crack in the battery. If
the battery connections are too loose, it could allow
vibration, causing the battery case seams to break
open. A leaking battery must be replaced.
Corrosion
Corrosion creates resistance in the charging circuit,
which causes undercharging and gradual starvation of
the battery.
To remove corrosion, clean the battery with a solution
of ordinary baking soda and a stiff, non-wire brush.
Then rinse the battery with clean water. DO NOT allow
the baking soda solution into the battery cells. Dry the
battery and ensure the battery terminal connections
are clean and tight. Clean terminals are very important
in a voltage regulated system.
NOTE: When washing the batteries, ensure the cell
caps are tight, preventing any cleaning solution from
entering the battery cells.
Acid Levels
The addition of acid will be necessary if considerable
electrolyte has been lost through spillage. Before
adding acid, ensure the battery is fully charged. This
is accomplished by putting the battery on a battery
charger and taking hourly specific gravity readings on
each cell. When all the cells are charged (gassing
freely) and three successive hourly readings show no
rise in specific gravity, the battery is considered fully
charged. Additional acid may now be added. Con-
tinue charging for another hour and again check the
specific gravity. Repeat the above process until all
cells indicate a specific gravity of 1.260 to 1.265 cor-
rected to 27°C (80°F).
NOTE: Use 1.400 strength sulfuric acid when making
specific gravity adjustments. Acid of higher strength
will attack the plates and separators before it has a
chance to diffuse into the solution.
If the temperature of the electrolyte is not reasonably
close to 27°C (80°F) when the specific gravity is
taken, the temperature factor must be corrected to
27°C (80°F):
• For every 5°C (10°F) below 27°C (80°F), subtract
0.004 from the specific gravity reading.
• For every 5°C (10°F) above 27°C (80°F), add
0.004 to the reading.
Non-Use or Storage
Remove idle batteries (unused for more than two
weeks) from the truck and place in a cool, dry place.
Periodically check and charge, when necessary.
Remember, all lead-acid batteries discharge slowly
when not in use. This self-discharge takes place even
though the battery is not connected in a circuit and is
more pronounced in warmer weather than in cold.
The rate of self-discharge of a battery kept at 38°C
(100°F) is about six times faster than that of a battery
kept at 19°C (50°F). Self-discharge of a battery kept
at 27°C (80°F) is about four times faster than that of
one at 10°C (50°F). Over a thirty day period, the
average self-discharge is about 0.002 specific gravity
per day at 27°C (80°F).