Subaru Legacy 2002 Service Manual page 516

= St + 0.0007 × (t − 20)
S
20
S : Specific gravity corrected at electro-
20
lyte temperature of 20°C
St : Measured specific gravity
t : Measured temperature (°C)
Determine whether or not battery must
be charged, according to corrected spe-
cific gravity.
Standard specific gravity: 1.220 — 1.290
[at 20°C (68°F)]
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:
¼ Do not bring an open flame close to the bat-
tery at this time.
CAUTION:
¼ Prior to charging, corroded terminals should
be cleaned with a brush and common baking
soda solution.
¼ Be careful since battery electrolyte over-
flows while charging the battery.
¼ Observe instructions when handling battery
charger.
¼ 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 spe-
cific 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.
BATTERY
G6M0103
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SC-19
2. CHECK HYDROMETER FOR STATE OF
CHARGE
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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.
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
temperature, 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 current range that will not increase the
electrolyte temperature 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:
¼ Observe the items in 1. NORMAL CHARG-
ING.
¼ Never use more than 10 amperes when
charging the battery because that will shorten
battery life.
Starting/Charging Systems
Required action
Load test
Charge battery
Replace battery*
(If cranking complaint)
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