Service Manual User Manual

Electrical System
10-47
Model 3606 • Origin 10/99
Note: The accuracy of this test procedure depends on
closely following the load, time and temperature specifi-
cations.
Relation of Battery Temperature to Minimum Voltage
TEMPERATURE MINIMUM VOLTAGE
70° F (21° C) and above 9.6
50° F (10° C) 9.4
30° F (-1° C) 9.1
15° F (-10° C) 8.8
0° F (-18° C) Below 0° F (-18° C)
d. Battery Charging
Charge rates between 3 and 50 amperes are generally
satisfactory as long as spewing of electrolyte does not
occur, or the battery does not feel excessively hot [over
125° F (52° C)]. Battery temperature can be estimated by
touching or feeling the battery case. If spewing of electro-
lyte occurs or temperature exceeds 125° F (52° C), com-
monly referred to as "boiling" the battery, the charging
rate must be reduced or temporarily halted to permit
cooling. Failure to do so will destroy the battery.
When charging a battery, keep this point in mind:
•
Battery charging
consists of a charge current
in
amperes
for a period of time
in hours
. Thus, a 25-
ampere charging rate for 2 hours would result in a
50-ampere hour charge to the battery.
The time required for a charge will vary due to the follow-
ing conditions:
•
Size of battery:
For example, a completely
discharged, large, heavy-duty battery requires more
than twice the recharging as a completely discharged
small passenger car battery.
•
Temperature:
For example, more time will be
required to charge a battery at 0° F than at 80° F.
When a fast charger is connected to a cold battery,
the current accepted by the battery will be very low at
first, then in time the battery will accept a higher rate
as the battery warms.
•
State of Charge:
A completely discharged battery
requires more than twice as much charge as a half-
charged battery. Because the electrolyte is nearly
pure water and therefore a poor conductor in a
completely discharged battery, the current accepted
is very low at first. Later, as the charging current
causes the electrolyte acid content to increase, the
charging current will likewise increase.
•
Charger Capacity:
A charger that can only supply
5 amperes will require a much longer period of
charging than a charger that can supply 30 amperes
or more.
e. Battery Troubleshooting
If a battery has tested satisfactorily but then fails to per-
form satisfactorily for no apparent reason, the following
items are among the more popular factors that may help
understand the cause:
1. Vehicle accessories left on, causing battery
discharge.
2. Charging system defect, such as slipping fan belt,
high wiring resistance, or faulty alternator.
3. A vehicle electrical load exceeds alternator output
capacity (common with the addition of electrical
accessories such as radio equipment, lights, air
conditioning, or window defogging/de-misting
devices).
4. Electrical system defects, such as shorted wires.
5. Extended slow speed driving with many accessories
on, and excessive engine idling (both cases do not
allow engine RPM to reach a sufficient speed to
enable alternator output to sufficiently charge the
battery).
6. Loose or poor battery cable-to-post connections,
previous improper charging of a run-down battery, or
loose battery hold-down hardware.
7. High resistance connections or defects in the starting
system.
8. Failure to disconnect the battery before long periods
of vehicle storage. Small current drains of vehicle
accessories that are connected all the time can also
discharge the battery in a six- to eight-week period. A
battery left in a discharged condition for a prolonged
period of time is subject to freezing and can become
difficult to recharge.
f. Jump Starting with
an Auxiliary (“ booster” ) Battery
Note: Use this information in addition to that found
under
C. Jump Starting
in
Section 2.12.15 Battery
.
Both the auxiliary or “booster” battery and the discharged
battery should be treated carefully when using jumper
cables. Follow the following procedure exactly, and DO
NOT cause sparks to occur:
1. Engage the park lock of the booster vehicle and
place its transmission in NEUTRAL (N). DO NOT
allow both vehicles to touch each other in any
manner, as this could establish a ground connection
and counteract the jump-starting process.