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Dodge Durango (HB). Manual - part 253

The battery is vented to release excess hydrogen gas that is created when the battery is being charged or dis-
charged. However, even with these vents, hydrogen gas can collect in or around the battery. If hydrogen gas is
exposed to flame or sparks, it may ignite. If the electrolyte level is low, the battery may arc internally and explode.
The battery must be replaced if the electrolyte level becomes low.

DIAGNOSIS AND TESTING

BATTERY

The battery must be completely charged and the terminals should be properly cleaned and inspected before diag-
nostic procedures are performed.

MICRO 420 BATTERY TESTER

The Micro 420 automotive battery tester is designed to assist the technician diagnose the cause of a defective
battery. Follow the instruction manual supplied with the tester to properly diagnose a battery.

WARNING: IF THE BATTERY SHOWS SIGNS OF FREEZING, LEAKING OR LOOSE POSTS, DO NOT TEST,
ASSIST-BOOST, OR CHARGE. THE BATTERY MAY ARC INTERNALLY AND EXPLODE. PERSONAL INJURY
AND/OR VEHICLE DAMAGE MAY RESULT.

WARNING: EXPLOSIVE HYDROGEN GAS FORMS IN AND AROUND THE BATTERY. DO NOT SMOKE, USE
FLAME, OR CREATE SPARKS NEAR THE BATTERY. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY
RESULT.

WARNING: THE BATTERY CONTAINS SULFURIC ACID, WHICH IS POISONOUS AND CAUSTIC. AVOID CON-
TACT WITH THE SKIN, EYES, OR CLOTHING. IN THE EVENT OF CONTACT, FLUSH WITH WATER AND CALL
A PHYSICIAN IMMEDIATELY. KEEP OUT OF THE REACH OF CHILDREN.

A battery that will not accept a charge is faulty, and must be replaced. Further testing is not required. A fully-charged
battery must be checked with Micro 420 tester or load tested to determine its cranking capacity. A battery that is
fully-charged, but does not pass the load test, is faulty and must be replaced.

Note: Completely discharged batteries may take several hours to accept a charge. Refer to Standard Pro-
cedures for the proper battery charging procedures.

STANDARD PROCEDURE

BATTERY CHARGING

Battery charging is the means by which the battery can be restored to its full voltage potential. A battery is fully-
charged when:

•

Micro 420 electrical system tester indicates battery is OK.

•

Three hydrometer tests, taken at one-hour intervals, indicate no increase in the temperature-corrected spe-
cific gravity of the battery electrolyte.

•

Passes Load test.

•

Open-circuit voltage of the battery is 12.65 volts or above.

WARNING: EXPLOSIVE HYDROGEN GAS FORMS IN AND AROUND THE BATTERY. DO NOT SMOKE, USE
FLAME, OR CREATE SPARKS NEAR THE BATTERY. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY
RESULT.

BATTERY SYSTEM

8F - 9

WARNING: IF THE BATTERY IS EQUIPPED WITH REMOVABLE CELL CAPS, BE CERTAIN THAT EACH OF
THE CELL CAPS IS IN PLACE AND TIGHT BEFORE THE BATTERY IS RETURNED TO SERVICE. PERSONAL
INJURY AND/OR VEHICLE DAMAGE MAY RESULT FROM LOOSE OR MISSING CELL CAPS.

CAUTION: Always disconnect and isolate the battery negative cable before charging a battery. Do not
exceed sixteen volts while charging a battery. Damage to the vehicle electrical system components may
result.

CAUTION: Battery electrolyte will bubble inside the battery case during normal battery charging. Electrolyte
boiling or being discharged from the battery vents indicates a battery overcharging condition. Immediately
reduce the charging rate or turn off the charger to evaluate the battery condition. Damage to the battery
may result from overcharging.

CAUTION: The battery should not be hot to the touch. If the battery feels hot to the touch, turn off the
charger and let the battery cool before continuing the charging operation. Damage to the battery may
result.

Some battery chargers are equipped with polarity-sensing circuitry. This circuitry protects the battery charger and
the battery from being damaged if they are improperly connected. If the battery state-of-charge is too low for the
polarity-sensing circuitry to detect, the battery charger will not operate. This makes it appear that the battery will not
accept charging current. See the instructions provided by the manufacturer of the battery charger for details on how
to bypass the polarity-sensing circuitry.

After the battery has been charged to 12.4 volts or greater, retest the battery using the Micro 420 tester or perform
a load test to determine the battery cranking capacity. If the battery will endure a load test, return the battery to
service. If the battery will not endure a load test, it is faulty and must be replaced.

Clean and inspect the battery hold downs, tray, terminals, posts, and top before completing battery service.

CHARGING A COMPLETELY DISCHARGED BATTERY

The following procedure should be used to recharge a
completely discharged battery. Unless this procedure
is properly followed, a good battery may be needlessly
replaced.

1. Measure the voltage at the battery posts with a

voltmeter, accurate to 1/10 (0.10) volt. If the read-
ing is below ten volts, the battery charging current
will be low. It could take some time before the bat-
tery accepts a current greater than a few milliam-
peres. Such low current may not be detectable on
the ammeters built into many battery chargers.

8F - 10

BATTERY SYSTEM

2. Disconnect and isolate the battery negative cable. Connect the battery charger leads. Some battery chargers are

equipped with polarity-sensing circuitry. This circuitry protects the battery charger and the battery from being
damaged if they are improperly connected. If the battery state-of-charge is too low for the polarity-sensing cir-
cuitry to detect, the battery charger will not operate. This makes it appear that the battery will not accept charging
current. See the instructions provided by the manufacturer of the battery charger for details on how to bypass the
polarity-sensing circuitry.

3. Battery chargers vary in the amount of voltage and current they provide. The amount of time required for a bat-

tery to accept measurable charging current at various voltages is shown in the Charge Rate Table. If the charg-
ing current is still not measurable at the end of the charging time, the battery is faulty and must be replaced. If
the charging current is measurable during the charging time, the battery may be good and the charging should
be completed in the normal manner.

CHARGE RATE TABLE

Voltage

Hours

16.0 volts maximum

up to 4 hours

14.0 to 15.9 volts

up to 8 hours

13.9 volts or less

up to 16 hours

CHARGING TIME REQUIRED

The time required to charge a battery will vary, depending upon the following factors:

•

Battery Capacity - A completely discharged heavy-duty battery requires twice the charging time of a small
capacity battery.

•

Temperature - A longer time will be needed to charge a battery at -18° C (0° F) than at 27° C (80° 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 charging time.

•

State-Of-Charge - A completely discharged battery 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 battery charges, the specific gravity of the electrolyte will gradually rise.

The Battery Charging Time Table gives an indication of the time required to charge a typical battery at room tem-
perature based upon the battery state-of-charge and the charger capacity.

BATTERY CHARGING TIME TABLE

Charging

Amperage

5 Amps

Amps

20 Amps

Open Circuit

Voltage

Hours Charging @ 21° C (70° F)

12.25 to 12.49

6 hours

3 hours

1.5

hours

12.00 to 12.24

10 hours

5 hours

2.5

hours

10.00 to 11.99

14 hours

7 hours

3.5

hours

Below 10.00

18 hours

9 hours

4.5

hours

BATTERY SYSTEM

8F - 11

IGNITION-OFF DRAW TEST

The term Ignition-Off Draw (IOD) identifies a normal 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
(0.005 to 0.035 ampere) with the ignition switch in the Off position, and all non-ignition controlled circuits in proper
working order. Up to thirty-five milliamperes are needed to enable the memory functions for the Powertrain Control
Module (PCM), digital clock, electronically tuned radio, and other modules which may vary with the vehicle equip-
ment.

A vehicle that has not been operated for approximately twenty days, may discharge the battery to an inadequate
level. When a vehicle will not be used for twenty days or more (stored), remove the IOD fuse from the Junction
Block (JB). 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 components.

•

An internally shorted generator.

•

Intermittent shorts in the wiring.

If the IOD is over thirty-five milliamperes, the problem must be found and corrected before replacing a battery. In
most cases, the battery can be charged and returned to service after the excessive IOD condition has been cor-
rected.

1. Verify that all electrical accessories are off. Turn off all lamps, remove the ignition key, and close all doors. If the

vehicle is equipped with an illuminated entry system or an electronically tuned radio, allow the electronic timer
function of these systems to automatically shut off (time out). This may take up to three minutes. See the Elec-
tronic Module Ignition-Off Draw Table for more information.

ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE

Module

Time Out?

(If Yes, Interval And Wake-Up Input)

IOD

IOD After Time

Out

Radio

1 to 3

milliamperes

N/A

Audio Power

Amplifier

up to 1

milliampere

N/A

Central Timer Module

(CTM)

4.75

milliamperes

(max.)

N/A

Powertrain Control

Module (PCM)

0.95 milliampere

N/A

ElectroMechanical

Instrument Cluster

(EMIC)

0.44 milliampere

N/A

Combination Flasher

0.08 milliampere

N/A

2. Determine that the underhood lamp is operating properly, then disconnect the lamp wire harness connector or

remove the lamp bulb.

3. Disconnect the battery negative cable.

8F - 12

BATTERY SYSTEM

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