Hummer H2. Manual - part 1121

Use a torque wrench in order to verify the torque to loosen the
positive battery terminal bolt.
Is the torque above the specified value?

10 N.m

(88 lb in)

Go to

Step 12

Go to

Step

Disconnect the positive battery cable.
Is the cable disconnected?

Go to

Step 13

1. Disconnect the positive battery cable.

2. Inspect for the following conditions and repair as needed:

The cable bolt is too long or deformed at the end.

There is foreign material present inside the nut in the
battery terminal.

Damage to the battery terminal face or cable connector
ring.

Is the repair complete?

Go to

Step 13

1. Clean and wire brush the lead face of both battery terminals and

the metal contact rings in both cable connectors.

2. Remove the bolts from the cable connectors in order to provide

access to the connector rings as needed.

3. If either of the battery terminals or the cable rings are

excessively damaged or corroded, replace as needed.

Are the metal connecting parts clean and in good condition?

Go to

Step 14

1. Connect the positive battery cable to the battery positive

terminal.

2. Tighten the cable bolt to the specified value.

Is the cable bolt properly tightened?

15 N.m

(11 lb ft)

Go to

Step 15

1. Connect the negative battery cable to the battery negative

terminal.

2. Tighten the cable bolt to the specified value.

Is the cable bolt properly tightened?

15 N.m

(11 lb ft)

Go to

Step 16

1. Install the J 42000 Battery Tester. See Special Tools and

Equipment .

2. Follow the directions supplied with the tester.

3. Follow any direction displayed on the tester.

Did the tester pass the battery?

IMPORTANT:

Ensure that all of the electrical loads are turned OFF.

Go to

Step 17

Go to

Step

2004 Hummer H2

2004 ELECTRICAL Engine Electrical - Hummer H2

BATTERY CHARGING

Tools Required

J 42000 Battery Tester. See Special Tools and Equipment .

For best results, use an automatic taper-rate battery charger with a voltage capability of 16 volts.

The charging area should be well ventilated.

Do not charge a battery that appears to be frozen. Allow the battery to warm to room temperature and test
it using the J 42000 before charging. See Special Tools and Equipment .

Battery State of Charge

The maintenance-free batteries SOC is estimated by reading the voltage of the battery across the battery
terminals. Because the voltage is affected by current flow into or out of the battery, the engine must be stopped
and all electrical loads turned OFF, including parasitic loads, when checking the voltage. The voltage can also
be affected if the battery has just been charged or discharged, so it is important to consider what has happened
to the battery in the time just before testing. Use the following procedure to determine the batteries SOC:

1. Be sure all electrical loads are turned OFF.

2. Determine whether the battery has been used in a vehicle or charged within the past 12 hours.

If the answer is no, the terminal voltage will be stabilized and no action is necessary before reading
the voltage. Skip to step 3.

1. Press the CODE button on the J 42000 . See Special Tools and

Equipment .

2. For warranty purposes, write the displayed code on the repair

order.

Did you complete this action?

Battery

1. Press the CODE button on the J 42000 . See Special Tools and

Equipment .

2. For warranty purposes, write the displayed code on the repair

order.

3. Replace the battery. Refer to Battery Replacement .

Did you complete the replacement?

Battery

Replace the battery. Refer to Battery Replacement .
Did you complete the replacement?

Battery

IMPORTANT: Using voltage to determine the batteries state of charge (SOC) is only accurate

after the battery has been at rest for 24 hours. This is enough time for the acid
in each cell to equalize. If the battery has been charged or discharged in the
past 24 hours, the battery SOC will only be an estimate.

2004 Hummer H2

2004 ELECTRICAL Engine Electrical - Hummer H2

If the answer is yes, terminal voltage will not be stabilized and you should wait 12 hours since the
last time the battery was used.

3. Estimate the battery temperature by determining the average temperature to which the battery has been

exposed for the past 12 hours.

4. Measure the battery voltage at the battery terminals. Refer to the following table to determine the SOC

according to the estimated battery temperature:

Battery Charging

Use the SOC information as follows:

A battery with a SOC that is below 65 percent must always be recharged before returning it to service or
continuing storage.

A battery with a SOC that is 65 percent or greater is generally considered to be charged enough in order
to be returned to normal service or in order to continue storage. However, if the battery is being used in
slow traffic or with short drive times, or if the temperature is very hot or very cold, the battery should be
fully charged, to at least 90 percent, before returning it to service or continuing storage.

Charging Time Required

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

The battery charger capacity-The higher the charger amperage, the less time it will take to charge the
battery.

The SOC of the battery-A completely discharged battery requires more than twice as much charging time
as a half charged battery. In a discharged battery with a voltage below 11 volts, the battery has a very
high internal resistance and may only accept a very low current at first. Later, as the charging current
causes the acid content to increase in the electrolyte, the charging current will increase. Extremely
discharged batteries may not activate the reversed voltage protection in some chargers. Refer to the
manufacturer's instructions for operating this circuitry.

The temperature of the battery-The colder the battery is, the more time it takes to recharge the battery.
The charging current accepted by a cold battery is very low at first. As the battery warms, the charging
current will increase.

IMPORTANT: The table is accurate to 10 percent only after the battery has been at rest

for 12 hours.

Battery Voltage

% Charge at 0° C (32° F)

% Charge at 25° C (75° F)

12.75 V

100%

12.7 V

100%

90%

12.6 V

90%

75%

12.45 V

75%

65%

12.2 V

65%

45%

12.0 V

40%

20%

2004 Hummer H2

2004 ELECTRICAL Engine Electrical - Hummer H2

Charging Procedure

When charging side-terminal batteries with the battery cables connected, connect the charger to the positive
cable bolt and to a ground located away from the battery. When charging side-terminal batteries with the battery
cables disconnected, install the battery side terminal adapters and connect the charger to the adapters.

Tighten: Tighten the battery side terminal adapters to 15 N.m (11 lb ft).

Use the following procedure to charge the battery:

1. Turn OFF the charger.

2. Ensure that all of the battery terminal connections are clean and tight.

3. Connect the charger positive lead to the battery positive terminal on the battery or the remote jumper stud

underhood.

4. Connect the negative charger lead to a solid engine ground or to a ground stud in the engine compartment

that is connected directly to the battery negative terminal, but away from the battery. If the negative
battery cable is disconnected and a terminal adapter is being used, connect directly to the adapter.

5. Turn ON the charger and set to the highest setting for normal charging.

6. Inspect the battery every half hour after starting the battery charger.

Charge the battery until the taper-rate charger indicates that the battery is fully charged.

Estimate the battery temperature by feeling the side of the battery. If it feels hot to the touch or its
temperature is over 45° C (125° F), discontinue charging and allow the battery to cool before
resuming charging.

7. After charging, test the battery. Refer to Battery Inspection/Test (Non-HP2) .

BATTERY ELECTRICAL DRAIN/PARASITIC LOAD TEST (W/BCM)

Tools Required

J 38758 Parasitic Draw Test Switch. See Special Tools and Equipment .

J 39200 Digital Multimeter

Battery Electrical Drain

NOTE:

Turn OFF the ignition when connecting or disconnecting the battery cables, the
battery charger or the jumper cables. Failure to do so may damage the PCM or
other electronic components.

NOTE:

Refer to Fastener Notice in Cautions and Notices.

NOTE:

Do not connect the negative charger lead to the housings of other vehicle
electrical accessories or equipment. The action of the battery charger may
damage such equipment.

2004 Hummer H2

2004 ELECTRICAL Engine Electrical - Hummer H2

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