Battery & Charging Systems: Overview Dodge Neon II

DESCRIPTION

A single 12-volt battery system 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 service information for the battery system in this vehicle covers the following related components, which are covered in further detail later in this section of the service manual

1. Battery - The storage battery provides a reliable means of storing a renewable source of electrical energy within the vehicle.
2. Battery Cables - The battery cables connect the positive and negatively charged battery terminal posts to the vehicle electrical system.
3. Battery Hold down - The battery hold down hardware secures the battery in the battery tray in the engine compartment.
4. Battery Thermal Guard - The battery thermal guard insulates the battery to protect it from engine compartment temperature extremes.
5. Battery Tray - The battery tray provides a secure mounting location in the vehicle for the battery and an anchor point for the battery hold down hardware.

For battery system maintenance schedules and jump starting procedures, see the owner's manual in the vehicle glove box. Optionally, refer to Lubrication and Maintenance for the proper battery jump starting procedures. While battery charging can be considered a maintenance procedure, the battery charging procedures and related information are located in the service procedures section of this service manual. This was done because the battery must be fully-charged before any battery system diagnosis or testing procedures can be performed. Refer to Standard Procedures for the proper battery charging procedures.

OPERATION

The battery system is designed to provide a safe, efficient, reliable and mobile 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 the 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 of any of the electrical components or circuits in the vehicle.

Scheme 2

Scheme 3

The battery, starting, and charging system 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 within this service manual 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 System for the proper charging system on-board diagnostic test procedures.

From the factory, most vehicles are equipped with a maintenance-free battery, and others with a low-maintenance battery.

Maintenance-free batteries have non-removable battery vent caps. (Scheme 4) Water cannot be added to this battery. Under normal service the composition of this battery reduces gassing and water loss at normal charge rates. If the battery electrolyte level becomes low, this battery must be replaced.

Scheme 4

Low-maintenance batteries have removable battery cell caps. Water can be added to this battery. Under normal service the composition of this battery reduces gassing and water loss at normal charge rates.

The battery is a device used to store electrical energy potential in a chemical form. When an electrical load is applied to the battery terminals, an electrochemical reaction occurs within the battery. This reaction causes the battery to discharge electrical current.

The battery is made up of six individual cells that are connected in series. Each cell contains positive charged plate groups made of lead oxide, and negatively charged plate groups made of sponge lead. The dissimilar metal plates are submerged in a sulfuric acid and water solution called an electrolyte.

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 dioxide, 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. If the electrolyte level is low, the battery may arc internally and explode. If the battery is equipped with removable cell caps, add distilled water whenever the electrolyte level is below the top of the plates. If the battery cell caps cannot be removed, the battery must be replaced if the electrolyte level becomes low.

The battery hold down includes one bolt and a hold down bracket. The battery hold down bracket consists of a formed steel bracket with one hole.

When installing a battery into the battery tray, it is important 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. Refer to Battery Hold down for the proper installation procedure, including the proper hold down fastener torque specifications.

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

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. The battery cables feature a clamping type female battery terminal made of soft lead that is die cast onto one end of the battery cable wire. A square headed 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 smaller female battery terminal clamp.

The battery cables cannot be repaired and, if damaged or faulty they must be replaced. 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 the appropriate wiring information in this service manual for the location of the proper battery cable wire harness diagrams. The wiring information also includes proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

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 for restoring 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 battery positive cable terminal clamp is die cast onto the ends of two wires. One wire has an eyelet terminal that connects the battery positive cable to the B(+) terminal stud of the Power Distribution Center (PDC), and the other wire has 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 also die cast onto 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 right side of 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 on the right front fender inner shield, near the battery.

The battery is placed in a plastic tray located in the left front side of the vehicle, next to the left strut tower. Refer to Battery Hold down for more information on hold down hardware.

The battery tray provides a secure mounting location and supports the battery. On some vehicles, the battery tray also provides the anchor point/s for the battery hold down hardware. The battery tray and the battery hold down 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.

Scheme 5

1. Remove the battery from the vehicle. Refer to the procedure in this section.
2. Remove two nuts to the rear and two bolts to the front of the battery tray. (Scheme 5)
3. Remove the tray retaining bolt under the center of the tray.
4. Slide battery tray out form under the air cleaner assembly. Do not remove the air cleaner assembly.
5. Remove battery tray from vehicle.

A flexible plastic bubble-wrap style thermal guard wraps around the battery case to enclose the sides of the battery. The thermal guard consists of a heavy black plastic outer skin and two lighter plies of plastic that have been formed into a sheet with hundreds of small air pockets entrapped between them.

The thermal guard protects the battery from engine compartment temperature extremes. The temperature of the battery can affect battery performance. The air trapped between the plastic plies of the thermal guard create a dead air space, which helps to insulate the sides of the battery case from the air temperature found in the surrounding engine compartment.

Scheme 6

1. Open hood.
2. Disconnect and isolate the battery negative cable then the positive cable.
3. Carefully lift the thermal guard off over the battery taking care not to rip it. (Scheme 6)
4. Remove the thermal guard from vehicle.

DESCRIPTION - CHARGING SYSTEM

The charging system consists of

1. Generator
2. Decoupler Pulley (If equipped)
3. Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM)
4. Ignition switch (refer to the Ignition System)
5. Battery (refer to «BATTERY SYSTEM»(ref-177669-S20625583082005060300000) )
6. Battery temperature sensor (calculated battery temperature if equipped)
7. Voltmeter (refer to the Instrument Cluster section for information if equipped)
8. Wiring harness and connections (refer to «SYSTEM WIRING DIAGRAMS»(ref-141298) )
9. Accessory drive belt (refer to «COOLING SYSTEMS»(ref-177701) )

OPERATION - CHARGING SYSTEM

The charging system is turned on and off with the ignition switch. The system is on when the engine is running and the ASD relay is energized. The ASD relay is energized when the PCM grounds the ASD control circuit. This voltage is connected through the PCM or IPM (intelligent power module) and supplied to one of the generator field terminals (Gen. Source +) at the back of the generator.

The generator is driven by the engine through a serpentine belt and pulley or decoupler pulley arrangement.

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.

Battery temperature is predicted using the values of 4 existing sensors inputs. These inputs are Inlet Air Sensor, Coolant Sensor, Vehicle Speed Sensor, and Fan State (on/off). The charging lamp will come on if either the inlet air temperature, coolant temperature, or vehicle speed sensor fail. If one of these sensors fail the charging system will default to 13.5 Volts. This temperature data, along with data from monitored line voltage (ASD voltage sense circuit), is used by the PCM to vary the battery charging rate. This is done by cycling the ground path to control the strength of the rotor magnetic field. The PCM then compensates and regulates generator current output accordingly to maintain system voltage at the targeted system voltage based on battery temperature.

All vehicles are equipped with On-Board Diagnostics (OBD). All OBD-sensed systems, including EVR (field control) circuitry, 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 certain failures it detects. Refer to On-Board Diagnostics in the Electronic Control Modules. (Refer to SELF-DIAGNOSTICS for more DTC information.

The Check Gauges Lamp (if equipped) monitors: charging system voltage , engine coolant temperature and engine oil pressure. If an extreme condition is indicated, the lamp will be illuminated. This is done as reminder to check the three gauges. The signal to activate the lamp is sent via the PCI bus circuits. The lamp is located on the instrument panel. Refer to the Instrument Cluster section for additional information.

The IAT sensor attaches to the intake air duct. (Scheme 7)

The IAT Sensor is a Negative Temperature Coefficient (NTC) Sensor that provides information to the PCM regarding the temperature of the air entering the intake manifold. The PCM sends 5 volts to the sensor and is grounded through the sensor return line. As temperature increases, resistance in the sensor decreases.

Scheme 7

The generator is belt-driven by the engine. It is serviced only as a complete assembly. If the generator fails for any reason, the entire assembly must be replaced. The generator produces DC voltage.

As the energized rotor begins to rotate within the generator, the spinning magnetic field induces a current into the windings of the stator coil.

The Y type stator winding connections deliver the induced AC current to 3 positive and 3 negative diodes for rectification. From the diodes, rectified DC current is delivered to the vehicles electrical system through the generator, battery, and ground terminals.

Noise emitting from the generator may be caused by

1. Worn, loose or defective bearings
2. Loose or defective drive pulley
3. Incorrect, worn, damaged or misadjusted drive belt
4. Loose mounting bolts
5. Misaligned drive pulley
6. Defective stator or diode
7. Damaged internal fins

Scheme 8

Scheme 9

Scheme 10

Scheme 11

1. Disconnect battery negative cable. (Scheme 8)
2. Loosen the jam nut and adjustment bolt.
3. Raise vehicle and support.
4. Remove accessary drive splash shield. (Scheme 9)
5. Loosen the lower mounting bolt.
6. Remove the generator drive belt.
7. Disconnect the generator field circuit wiring connector. Push the RED locking tab to release.
8. Remove the B+ terminal nut and wire.
9. Remove the upper and lower mounting bolt and move generator off of pivot bracket. (Scheme 10)
10. Remove pivot bracket.
11. Remove Generator through wheel well. (Scheme 11)

The Electronic Voltage Regulator (EVR) is not a separate component. It is actually a voltage regulating circuit located within the Powertrain Control Module (PCM). The EVR is not serviced separately. If replacement is necessary, the PCM must be replaced.

The amount of DC current produced by the generator is controlled by EVR circuitry contained within the PCM. This circuitry is connected in series with the generators second rotor field terminal and its ground.

Voltage is regulated by cycling the ground path to control the strength of the rotor magnetic field. The EVR circuitry monitors system line voltage (B+) and calculated battery temperature or inlet air temperature sensor (refer to Battery Temperature Sensor or Inlet Air Temperature Sensor, if equipped, for more information). It then determines a target charging voltage. If sensed battery voltage is lower than the target voltage, the PCM grounds the field winding until sensed battery voltage is at the target voltage. A circuit in the PCM cycles the ground side of the generator field at 250 times per second (250 Hz), but has the capability to ground the field control wire 100% of the time (full field) to achieve the target voltage. If the charging rate cannot be monitored (limp-in), a duty cycle of 25% is used by the PCM in order to have some generator output. Also refer to Charging System Operation for additional information.