Hummer H2. Manual - part 1183

Fig. 65: Battery Ground Negative Cable & Bolt 
Courtesy of GENERAL MOTORS CORP. 

7. Connect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure 

(Single Battery) .  

DESCRIPTION AND OPERATION 

BATTERY DESCRIPTION AND OPERATION 

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

Fig. 66: View Of Battery Danger Label 
Courtesy of GENERAL MOTORS CORP. 

The maintenance free battery is standard. There are no vent plugs in the cover. The battery is completely sealed 
except for 2 small vent holes in the side. These vent holes allow the small amount of gas that is produced in the 
battery to escape. 

The battery has 3 functions as a major source of energy: 

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Engine cranking  

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Voltage stabilizer  

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Alternate source of energy with generator overload  

The battery specification label, example below, contains information about the following: 

CAUTION: Batteries produce explosive gases, contain corrosive acid, and supply 

levels of electrical current high enough to cause burns. Therefore, to 
reduce the risk of personal injury when working near a battery: 

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Always shield your eyes and avoid leaning over the battery whenever 
possible.  

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Do not expose the battery to open flames or sparks.  

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Do not allow the battery electrolyte to contact the eyes or the skin. 
Flush immediately and thoroughly any contacted areas with water 
and get medical help.  

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Follow each step of the jump starting procedure in order.  

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Treat both the booster and the discharged batteries carefully when 
using the jumper cables.  

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

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The test ratings  

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The original equipment catalog number  

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The recommended replacement model number  

Fig. 67: Battery Specification Label 
Courtesy of GENERAL MOTORS CORP. 

Battery Ratings 

A battery has 2 ratings: 

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Reserve capacity  

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Cold cranking amperage  

When a battery is replaced use a battery with similar ratings. Refer to the battery specification label on the 
original battery or refer to Battery Usage . 

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

Reserve Capacity 

Reserve capacity is the amount of time in minutes it takes a fully charged battery, being discharged at a constant 
rate of 25 amperes and a constant temperature of 27° C (80° F) to reach a terminal voltage of 10.5 volts. Refer 
to Battery Usage for the reserve capacity rating of the original equipment battery. 

Cold Cranking Amperage 

The cold cranking amperage is an indication of the ability of the battery to crank the engine at cold 
temperatures. The cold cranking amperage rating is the minimum amperage the battery must maintain for 30 
seconds at -18° C (0° F) while maintaining at least 7.2 volts. Refer to Battery Usage for the cold cranking 
amperage rating for this vehicle. 

CHARGING SYSTEM DESCRIPTION AND OPERATION 

Generator 

The AD-244 generator is non-repairable. They are electrically similar to earlier models. The generators feature 
the following major components: 

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The delta stator  

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The rectifier bridge  

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The rotor with slip rings and brushes  

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A conventional pulley  

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Dual internal fans  

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A voltage regulator  

The pulley and the fan cool the slip ring and the frame. 

The AD stands for Air-cooled Dual internal fan; the 2 is an electrical design designator; the 30/44 denotes the 
outside diameter of the stator laminations in millimeters, over 100 millimeters. The generators is rated at 145 
amperes. 

The generator features permanently lubricated bearings. Service should only include the tightening of mounting 
components. Otherwise, the generator is replaced as a complete unit. 

Regulator 

The voltage regulator controls the field current of the rotor in order to limit system voltage. The regulator 
switches the current on and off at a rate of 400 cycles per second in order to perform the following functions: 

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Radio noise control  

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Obtain the correct average current needed for proper system voltage control  

At high speeds, the on-time may be 10 percent with the off-time at 90 percent. At low speeds, the on-time may 

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2