Chevrolet Silverado / GMC Sierra. Service manual — part 1787

8. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and

Connection (w/Single Battery) or Battery Negative Cable Disconnection and
Connection (w/Auxiliary Battery) or Battery Negative Cable Disconnection and
Connection (w/Dual Batteries).

DESCRIPTION AND OPERATION

BATTERY DESCRIPTION AND OPERATION

Fig. 317: View Of Battery Danger Label
Courtesy of GENERAL MOTORS CORP.

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:

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

Do not expose the battery to open flames or sparks.

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.

Follow each step of the jump starting procedure in order.

Treat both the booster and the discharged batteries

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Batteries that are no longer wanted must be disposed of by an approved battery recycler and must
never be thrown in the trash or sent to a landfill.

Batteries that are not part of the vehicle itself, not the battery under the hood, must only be
transported on public streets for business purposes via approved hazardous material transportation
procedures.

Battery storage, charging, and testing facilities in repair shops must meet various requirements for
ventilation, safety equipment, material segregation, etc.

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:

Engine cranking

Voltage stabilizer

Alternate source of energy with generator overload

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

The test ratings

The original equipment catalog number

The recommended replacement model number

carefully when using the jumper cables.

IMPORTANT: Because of the materials used in the manufacture of automotive

lead-acid batteries, dealers and service shops that handle them
are subject to various regulations issued by OSHA, EPA, DOT,
and various state or local agencies. Other regulations may also
apply in other locations. Always know and follow these
regulations when handling batteries.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Fig. 318: View Of Battery Specification Label
Courtesy of GENERAL MOTORS CORP.

Battery Ratings

A battery may have 3 ratings:

Amp hour (AH)

Reserve capacity (RC)

Cold cranking amperage (CCA)

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.

Amp Hour (AH)

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

The amp hour rating of a battery is the amount of time it takes a fully charged battery, being
discharged at a constant rate of 1 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 amp hour rating of the original
equipment battery.

Reserve Capacity (RC)

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 (CCA)

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.

Auxiliary Battery

Auxiliary batteries are an available option on vehicles where many accessories can be utilized
such as TVs, radios, lights, computers, etc. The charging of these batteries is explained in
charging system description and operation. Also, the auxiliary battery is only for accessory use
and not part of the starting system.

CHARGING SYSTEM DESCRIPTION AND OPERATION

Electrical Power Management (EPM) Overview

The electrical power management (EPM) system is designed to monitor and control the charging
system and send diagnostic messages to alert the driver of possible problems with the battery and
generator. This EPM system primarily utilizes existing on-board computer capability to maximize
the effectiveness of the generator, to manage the load, improve battery state-of-charge and life,
and minimize the system's impact on fuel economy. The EPM system performs 3 functions:

It monitors the battery voltage and estimates the battery condition.

It takes corrective actions by boosting idle speeds, and adjusting the regulated voltage.

It performs diagnostics and driver notification.

The battery condition is estimated during ignition-off and during ignition-on. During ignition-off
the state-of-charge (SOC) of the battery is determined by measuring the open-circuit voltage. The

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado