Standard Procedure - Open-Circuit Voltage Test; Standard Procedure - Ignition-Off Draw Test - Chrysler Dodge Caravan 2002 Manual

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BATTERY (Continued)
F). When a fast battery charger is connected to a cold
battery, the current accepted by the battery will be
very low at first. As the battery warms, it will accept
a higher charging current rate (amperage).
• Charger Capacity - A battery charger that
supplies only five amperes will require a longer
charging time. A battery charger that supplies
twenty amperes or more will require a shorter charg-
ing time.
• State-Of-Charge - A completely discharged bat-
tery requires more charging time than a partially
discharged battery. Electrolyte is nearly pure water
in a completely discharged battery. At first, the
charging current (amperage) will be low. As the bat-
tery charges, the specific gravity of the electrolyte
will gradually rise.
The Conventional Battery Charging Time Table
gives an indication of the time required to charge a
typical battery at room temperature based upon the
battery state-of-charge and the charger capacity.
CONVENTIONAL BATTERY CHARGING TIME
Charging
5 Amps
Amperage
Open Circuit
Hours Charging @ 21° C (70° F)
Voltage
12.25 to 12.49 6 hours
12.00 to 12.24 10 hours
10.00 to 11.99 14 hours
Below 10.00 18 hours
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST
A battery open-circuit voltage (no load) test will show
the approximate state-of-charge of a battery. This test
can be used if no other battery tester is available.
Before proceeding with this test, completely charge
the battery. Refer to Standard Procedures for the
proper battery charging procedures.
(1) Before measuring the open-circuit voltage, the
surface charge must be removed from the battery.
Turn on the headlamps for fifteen seconds, then allow
up to five minutes for the battery voltage to stabilize.
(2) Disconnect and isolate both battery cables, neg-
ative cable first.
(3) Using a voltmeter connected to the battery
posts (see the instructions provided by the manufac-
turer of the voltmeter), measure the open-circuit volt-
age (Fig. 9).
See the Open-Circuit Voltage Table. This voltage
reading will indicate the battery state-of-charge, but
will not reveal its cranking capacity. If a battery has
an open-circuit voltage reading of 12.4 volts or
TABLE
10
20 Amps
Amps
3 hours 1.5 hours
5 hours 2.5 hours
7 hours 3.5 hours
9 hours 4.5 hours
BATTERY SYSTEM
Fig. 9 Testing Open-Circuit Voltage - Typical
greater, it may be load tested to reveal its cranking
capacity. Refer to Standard Procedures for the proper
battery load test procedures.
OPEN CIRCUIT VOLTAGE TABLE
Open Circuit Voltage
11.7 volts or less
12.0 volts
12.2 volts
12.45 volts
12.65 volts or more
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to thirty-five milliamperes (0.015 to 0.025 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. Up to twenty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty-one days, may discharge the battery
to an inadequate level. When a vehicle will not be
used for twenty-one days or more (stored), remove
the IOD fuse from the Integrated Power Module
(IPM). This will reduce battery discharging.
Excessive IOD can be caused by:
• Electrical items left on.
• Faulty or improperly adjusted switches.
• Faulty or shorted electronic modules and compo-
nents.
• An internally shorted generator.
8Fa - 13
Charge Percentage
0%
25%
50%
75%
100%