Subaru Impreza 2003, Service Manual

Page: 410 / 3610

SC(H4SO)-20
STARTING/CHARGING SYSTEMS
BATTERY
4. Battery
A: REMOVAL
1) Disconnect the positive (+) cable after discon-
necting the ground (
−
) cable of battery.
2) Remove the flange nuts from battery rods, and
then take off the battery holder.
3) Remove the battery.
B: INSTALLATION
Install in the reverse order of removal.
Tightening torque:
3.4 N·m (0.35 kgf-m, 2.5 ft-lb)
NOTE:
• Clean the battery cable terminals, and then apply
grease to retard formation of corrosion.
• Connect the positive (+) cable of battery and then
the ground (
−
) cable of battery.
C: INSPECTION
WARNING:
• Electrolyte has toxicity; be careful handling
the fluid.
• Avoid contact with skin, eyes or clothing. Es-
pecially at contact with eyes, flush with running
water for 15 minutes and get prompt medical at-
tention.
• Batteries produce explosive gasses. Keep
sparks, flame, cigarettes away.
• Ventilate when charging or using in enclosed
space.
• For safety, in case an explosion does occur,
wear eye protection or shield your eyes when
working near any battery. Never lean over a bat-
tery.
• Do not let the battery fluid contact eyes, skin,
fabrics, or paint-work because battery fluid is
corrosive acid.
• To lessen the risk of sparks, remove rings,
metal watch-bands, and other metal jewelry.
Never allow metal tools to contact the positive
battery terminal and anything connected to it
while you are at the same time in contact with
any other metallic portion of the vehicle. This
may cause a short circuit.
1. EXTERNAL PARTS:
Check for the existence of dirt or cracks on battery
case, top cover, vent plugs, and terminal posts. If
necessary, clean with water and wipe with a dry
cloth.
Apply a thin coat of grease on the terminal posts to
prevent corrosion.
2. ELECTROLYTE LEVEL:
Check the electrolyte level in each cell. If the level
is below MIN LEVEL, bring the level to MAX LEVEL
by pouring distilled water into the battery cell. Do
not fill beyond MAX LEVEL.
3. SPECIFIC GRAVITY OF ELECTROLYTE:
1) Measure the specific gravity of electrolyte using
a hydrometer and a thermometer.
Specific gravity varies with temperature of electro-
lyte so that it must be corrected at 20
°
C (68
°
F) us-
ing the following equation:
S
20
= St + 0.0007
××××
(t
−−−−
20)
S
20
: Specific gravity corrected at electrolyte
temperature of 20
°°°°
C
St: Measured specific gravity
t: Measured temperature (
°°°°
C)
Determine whether or not battery must be
charged, according to corrected specific
gravity.
Standard specific gravity: 1.220 — 1.290 [at
20
°°°°
C (68
°°°°
F)]
2) Measuring the specific gravity of the electrolyte
in battery will disclose the state of charge of bat-
tery. The relation between specific gravity and state
of charge is as shown in the figure.
SC-00053
SC-00094
1.28
Specific gravity [20˚C (68˚F)]
Specific gravity and state of charge
Complete charge
Charging condition
1.26
1.24
1.22
1.20
1.18
1.16
1.14
1.12
100% 75% 50% 22% 0%
(%)