Komatsu 830E-AC Shop Manual page 194

To remove corrosion, clean the battery with a solu-
tion of ordinary baking soda and a stiff, non-wire
brush and flush with clean water. Make sure that
none of the soda solution is allowed to enter the bat-
tery cells. Make sure that the terminals are clean and
tight. Clean terminals are very important in a voltage
regulated system. Corrosion creates resistance in
the charging circuit, which causes undercharging and
gradual starvation of the battery.
NOTE: When washing batteries, make sure that the
cell caps are tight to prevent cleaning solution from
entering the cells.
Addition of acid will be necessary if considerable
electrolyte has been lost through spillage. Before
adding acid, make sure that the battery is fully
charged by putting the battery on charge and taking
hourly specific gravity readings on each cell. When
all the cells are gassing freely and three successive
hourly readings show no rise in specific gravity, the
battery is considered charged. Additional acid may
now be added. Continue charging for another hour
and check specific gravity again. Repeat the above
procedure until all cells indicate a specific gravity of
1.260 - 1.265 corrected to 27°C (80°F).
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, temperature should be corrected to 27°C
(80°F) as follows:
• For every 5°C (10°F) below 27°C (80°F), 0.004
should be SUBTRACTED from the specific
gravity reading.
• For every 5°C (10°F) above 27°C (80°F), 0.004
should be ADDED to the reading.
Idle batteries should not be allowed to stand
unattended. If equipment is to stand unused for more
than two weeks, the batteries should be removed
and placed in a cool, dry place where they may be
checked periodically and charged 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 it is more pronounced in warm weather than in
cold weather.
D2-4
The rate of self-discharge of a battery kept at 38°C
(100°F) is about six times that of a battery kept at
10°F (50°F), and self-discharge of a battery kept at
27°C (80°F) is about four times that one at 10°F
(50°F). Over a 30 day period, the average self-dis-
charge runs about 0.002 specific gravity per day at
27°C (80°F).
To offset the results of self-discharge, idle batteries
should receive a booster charge (not a quick charge)
at least once every 30 days. Batteries allowed to
stand for long periods in a discharged condition are
attacked by a crystallization of the lead sulfate on the
plates. Such batteries are called "sulfated" and are,
in the majority of cases, irreparably damaged. In less
severe cases, the sulfated battery may be restored to
limited service by prolonged charging at a low rate
(approximately 1/2 normal rate).
An undercharged battery is extremely susceptible to
freezing when allowed to stand in cold weather.
The electrolyte of a battery in various stages of
charge will start to freeze at temperatures indicated
in the table below.
The temperatures in the table below indicate the
points at which the first ice crystals appear. Lower
temperatures must be reached for a solid freeze.
Solid freezing of the electrolyte may crack the battery
case and damage the positive plates. As will be
noted, a charged battery is in no danger of freezing.
Therefore, a battery should be kept charged, espe-
cially during winter weather.
SPECIFIC GRAVITY
Corrected to 27°C (80°F)
24 VDC Electric Supply System
FREEZING
TEMPERATURE
1.280 -70°C (-90°F)
1.250 -54°C (-60°F)
1.200 -27°C (-16°F)
1.150 -15°C (+5°F)
1.100 -7°C (+19°F)
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