Subaru Legacy 2003 Service Manual page 396

2) Measuring the specific gravity of the electrolyte
in the battery will disclose the state of charge of the
battery. The relation between the specific gravity
and the state of charge is as shown in figure.
D: MEASUREMENT
WARNING:
• Do not bring an open flame close to the bat-
tery at this time.
CAUTION:
• Prior to charging, corroded terminals should
be cleaned with a brush and common baking
soda solution.
• Be careful since battery electrolyte overflows
while charging the battery.
• Observe instructions when handling battery
charger.
• Before charging the battery on vehicle, dis-
connect battery ground terminal. Failure to fol-
low this rule may damage alternator's diodes or
other electrical units.
1. JUDGMENT OF BATTERY IN CHARGED
CONDITION
1) Specific gravity of electrolyte is held at a specific
value in a range from 1.250 to 1.290 for more than
one hour.
2) Voltage per battery cell is held at a specific value
in a range from 2.5 to 2.8 volts for more than one
hour.
2. CHECK HYDROMETER FOR STATE OF
CHARGE
Hydrometer
State of charge
indicator
Green dot Above 65%
Dark dot Below 65%
Clear dot Low electrolyte
*: Check electrical system before replacement.
3. NORMAL CHARGING
Charge the battery at current value specified by
manufacturer or at approximately 1/10 of battery's
ampere-hour rating.
BATTERY
Required action
Load test
Charge battery
Replace battery*
(If cranking complaint)
SC(H4SO)-21
STARTING/CHARGING SYSTEMS
4. QUICK CHARGING
Quick charging is a method in which the battery is
charged in a short period of time with a relatively
large current by using a quick charger.
Since a large current flow raises electrolyte temper-
ature, the battery is subject to damage if the large
current is used for prolonged time. For this reason,
the quick charging must be carried out within a cur-
rent range that will not increase the electrolyte tem-
perature above 40°C (104°F).
It should be also remembered that the quick charg-
ing is a temporary means to bring battery voltage
up to a fair value and, as a rule, a battery should be
charged slowly with a low current.
CAUTION:
• Observe the items in 3. NORMAL CHARGING.
• Never use more than 10 amperes when
charging the battery because that will shorten
battery life.