Subaru Impreza 2003 Service Manual page 411

D: MEASUREMENT
WARNING:
Do not bring an open flame close to the battery
at this time.
CAUTION:
• Prior to charging, corroded terminals should
be cleaned with a brush and common caustic
soda solution.
• Be careful since the battery electrolyte over-
flows while charging the battery.
• Observe the instructions when handling bat-
tery charger.
• Before charging the battery on vehicle, dis-
connect battery ground terminal to prevent
damage of generator diodes or other electrical
units.
1. JUDGMENT OF BATTERY IN CHARGED
CONDITION
1) Specific gravity of electrolyte is held within the
specified range from 1.250 to 1.290 for more than
one hour.
2) Voltage per battery cell is held at the specified
range from 2.5 to 2.8 volts for more than one hour.
2. STATE OF CHARGE CHECK USING A
HYDROMETER
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 approx. 1/10 of the battery's am-
pere-hour rating.
BATTERY
Corrective action
Load test
Charge battery
Replace battery*
(If cranking is difficult)
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 large cur-
rent is used for prolonged time. For this reason, the
quick charging must be carried out within a current
range that will not increase the electrolyte temper-
ature 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.