Battery System: Overview Chrysler Pacifica CS

DESCRIPTION

A single 12-volt battery is standard factory-installed equipment on this model. All of the components of the battery system are located within the engine compartment of the vehicle. The battery system is comprised of the following related components, which are covered in further detail later in this article

1. Battery - The maintenance-free 12 volt automotive battery provides a reliable means of storing a renewable source of electrical energy within the vehicle.
2. Battery Cables - The color-coded positive and negative battery cables connect the positive and negative battery terminal posts to the vehicle electrical system.
3. Battery Holddown - The battery holddown secures the battery in the battery tray.
4. Battery Thermowrap - The battery thermowarp insulates the battery from engine compartment temperature extremes.
5. Battery Tray - The battery tray provides a secure mounting location in the engine compartment for the battery and an anchor point for the battery holddown.

For battery maintenance schedules and jump starting procedure, see the owner's manual in the vehicle glove box. Optionally, refer to the LUBRICATION & MAINTENANCE for the battery maintenance schedules and proper battery jump starting procedure. While battery charging can be considered a maintenance procedure, the battery charging procedure and related information are located later in this article.

OPERATION

The battery system is designed to provide a safe, efficient and reliable means of delivering and storing electrical energy. This electrical energy is required to operate the engine starting system, as well as to operate many of the other vehicle accessory systems for limited durations while the engine and/or charging system are not operating. The battery system is also designed to provide a reserve of electrical energy to supplement the charging system for short durations while the engine is running and the electrical current demands of the vehicle exceed the output of the charging system. In addition to delivering, and storing electrical energy for the vehicle, the battery system serves as a capacitor and voltage stabilizer for the vehicle electrical system. It absorbs most abnormal or transient voltages caused by the switching ON/OFF of any of the electrical components or circuits in the vehicle.

The battery, starting, and charging systems in the vehicle operate with one another and must be tested as a complete system. In order for the engine to start and the battery to maintain its charge properly, all of the components that are used in these systems must perform within specifications. It is important that the battery, starting, and charging systems be thoroughly tested and inspected any time a battery needs to be charged or replaced. The cause of abnormal battery discharge, overcharging or early battery failure must be diagnosed and corrected before a battery is replaced and before a vehicle is returned to service. The service information for these systems has been separated into other articles (Refer to CHARGING and STARTING to make it easier to locate the specific information you are seeking. However, when attempting to diagnose any of these systems, it is important that you keep their interdependency in mind.

The diagnostic procedures used for the battery, starting, and charging systems include the most basic conventional diagnostic methods, to the more sophisticated On-Board Diagnostics (OBD) built into the Powertrain Control Module (PCM). Use of an induction-type milliampere ammeter, a volt/ohmmeter, a battery charger, a carbon pile rheostat (load tester) and a 12-volt test lamp may be required. All OBD-sensed systems are monitored by the PCM. Each monitored circuit is assigned a Diagnostic Trouble Code (DTC). The PCM will store a DTC in electronic memory for any failure it detects. Refer to CHARGING for the proper charging system on-board diagnostic test procedures.

Maintenance-free batteries are standard factory-installed equipment on this model. Male post type terminals made of a soft lead material protrude from the top of the molded plastic battery case. (Scheme 2)to provide the means for connecting the battery to the vehicle electrical system. The battery positive terminal post is visibly larger in diameter than the negative terminal post. The letters POS and NEG are also molded into the top of the battery case adjacent to their respective positive and negative terminal posts for additional identification confirmation.

Scheme 2

This battery is designed to provide a safe, efficient and reliable means of storing electrical energy in a chemical form. This means of energy storage allows the battery to produce the electrical energy required to operate the engine starting system, as well as to operate many of the other vehicle accessory systems for limited durations while the engine and/or the charging system are not operating. The battery is made up of six individual cells that are connected in series. Each cell contains positively charged plate groups that are connected with lead straps to the positive terminal post, and negatively charged plate groups that are connected with lead straps to the negative terminal post. Each plate consists of a stiff mesh framework or grid coated with lead dioxide (positive plate) or sponge lead (negative plate). Insulators or plate separators made of a non-conductive material are inserted between the positive and negative plates to prevent them from contacting or shorting against one another. These dissimilar metal plates are submerged in a sulfuric acid and water solution called electrolyte.

The chemical composition of the metal coated plates within the low-maintenance battery reduces battery gassing and water loss, at normal charge and discharge rates. Therefore, the battery should not require additional water in normal service. However, rapid loss of electrolyte can be caused by an overcharging condition. Be certain to diagnose the charging system after replacing the battery for a low electrolyte condition and before returning the vehicle to service. Refer to CHARGING for additional information.

The battery Group Size number, the Cold Cranking Amperage (CCA) rating, and the Reserve Capacity (RC) rating or Ampere-Hours (AH) rating can be found on the original equipment battery label. Be certain that a replacement battery has the correct Group Size number, as well as CCA, and RC or AH ratings that equal or exceed the original equipment specification for the vehicle being serviced. Refer to SPECIFICATIONS for the proper factory-installed battery specifications.

The battery is designed to store electrical energy in a chemical form. When an electrical load is applied to the terminals of the battery, an electrochemical reaction occurs. This reaction causes the battery to discharge electrical current from its terminals. As the battery discharges, a gradual chemical change takes place within each cell. The sulfuric acid in the electrolyte combines with the plate materials, causing both plates to slowly change to lead sulfate. At the same time, oxygen from the positive plate material combines with hydrogen from the sulfuric acid, causing the electrolyte to become mainly water. The chemical changes within the battery are caused by the movement of excess or free electrons between the positive and negative plate groups. This movement of electrons produces a flow of electrical current through the load device attached to the battery terminals.

As the plate materials become more similar chemically, and the electrolyte becomes less acid, the voltage potential of each cell is reduced. However, by charging the battery with a voltage higher than that of the battery itself, the battery discharging process is reversed. Charging the battery gradually changes the sulfated lead plates back into sponge lead and lead oxide, and the water back into sulfuric acid. This action restores the difference in the electron charges deposited on the plates, and the voltage potential of the battery cells. For a battery to remain useful, it must be able to produce high-amperage current over an extended period. A battery must also be able to accept a charge, so that its voltage potential may be restored.

The battery is vented to release excess hydrogen gas that is created when the battery is being charged or discharged. 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.

The battery hold down hardware consists of a molded plastic lip that is integral to the outboard edge of the battery tray and support unit, a molded steel hold down bracket and a single hex nut with a coned washer.

When installing a battery into the battery tray, be certain that the hold down hardware is properly installed and that the fasteners are tightened to the proper specifications. Improper hold down fastener tightness, whether too loose or too tight, can result in damage to the battery, the vehicle or both.

The battery holddown secures the battery in the battery tray. This holddown is designed to prevent battery movement during the most extreme vehicle operation conditions. Periodic removal and lubrication of the battery holddown hardware is recommended to prevent hardware seizure at a later date.

Note. Never operate a vehicle without a battery holddown device properly installed. Damage to the vehicle, components and battery could result.

The battery cables are large gauge, stranded copper wires sheathed within a heavy plastic or synthetic rubber insulating jacket. The wire used in the battery cables combines excellent flexibility and reliability with high electrical current carrying capacity.

A clamping type female battery terminal made of stamped metal is attached to one end of the battery cable wire. A pinch-bolt and hex nut are installed at the open end of the female battery terminal clamp. Large eyelet type terminals are crimped onto the opposite end of the battery cable wire and then solder-dipped. The battery positive cable wires have a red insulating jacket to provide visual identification and feature a larger female battery terminal clamp to allow connection to the larger battery positive terminal post. The battery negative cable wires have a black insulating jacket and a slightly smaller female battery terminal clamp.

Both the battery positive and negative cables are available for service replacement only as a unit with the battery wire harness, which may include portions of the wiring circuits for the generator and other components on some models. Refer to Wiring for the location of more information on the various wiring circuits included in the battery wire harness for the vehicle being serviced.

The battery cables connect the battery terminal posts to the vehicle electrical system. These cables also provide a path back to the battery for electrical current generated by the charging system to restore the voltage potential of the battery. The female battery terminal clamps on the ends of the battery cable wires provide a strong and reliable connection of the battery cable to the battery terminal posts. The terminal pinch bolts allow the female terminal clamps to be tightened around the male terminal posts on the top of the battery. The eyelet terminals secured to the opposite ends of the battery cable wires from the female battery terminal clamps provide secure and reliable connection of the battery cables to the vehicle electrical system.

The positive battery cable wire has an eyelet terminal that connects to the B(+) terminal stud of the Integrated Power Module (IPM), and an eyelet terminal that connects the battery positive cable to the B(+) terminal stud of the engine starter motor solenoid. The battery negative cable terminal clamp is attached to the ends of two wires. One wire has an eyelet terminal that connects the battery negative cable to the vehicle powertrain through a stud on the engine cylinder block. The other wire has an eyelet terminal that connects the battery negative cable to the vehicle body through a ground screw in the engine compartment.

The battery is mounted in a molded plastic battery tray and support unit located in the left front corner of the engine compartment. The battery tray and support unit is secured with three fasteners, Two are located directly under the battery and the other is located on the right side of the tray.

The battery tray and support unit also includes a drainage hose, located in the front of the unit.

The battery tray provides a secure mounting location and supports the battery. The battery tray also provides the anchor point for the battery holddown hardware. The battery tray and the battery holddown hardware combine to secure and stabilize the battery in the engine compartment, which prevents battery movement during vehicle operation. Unrestrained battery movement during vehicle operation could result in damage to the vehicle, the battery, or both.

The battery tray used on this model also includes a drainage hose, which provides means for any liquid that might collect in the bottom of the battery tray to drain under the vehicle.

Scheme 3

1. Disconnect and isolate the negative battery cable.
2. Remove the battery from the vehicle. Refer «REMOVAL»(ref-245419-S07598234782006110200000). 1 - Battery Tray Drain Hole/Hose Attachment 2 - Battery Tray 3 - Retaining Fasteners
3. Remove the battery tray retaining fasteners. (Scheme 3)
4. Pull battery tray up far enough to disconnect the drain hose assembly.
5. Remove the battery tray from the vehicle.

A one-piece slip-on thermowrap unit shields the battery case from engine compartment heat. The thermowrap slips over the battery case. see scheme 14and acts like a protective jacket.

The thermowrap protects the battery from engine compartment temperature extremes. The temperature of the battery can affect battery life. The air trapped in the padded material of the thermowrap creates a dead air space, which helps to insulate the sides of the battery case from the air temperature found in the surrounding engine compartment.