Battery: Description and Operation
BATTERY SYSTEMA single 12-volt battery system is standard factory-installed equipment on gasoline engine equipped models. Models equipped with a diesel engine utilize two 12-volt batteries connected in parallel. 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:
- Battery - The storage battery provides a reliable means of storing a renewable source of electrical energy within the vehicle.
- Battery Cable - The battery cables connect the battery terminal posts to the vehicle electrical system.
- Battery Holddown - The battery holddown hardware secures the battery in the battery tray in the engine compartment.
- Battery Tray - The battery tray provides a secure mounting location in the vehicle for the battery and an anchor point for the battery holddown 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 recommended battery maintenance schedules and 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 standard procedures section. 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.
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.
Fig. 4 Low-Maintenance Battery - Typical:
BATTERY
A large capacity, low-maintenance storage battery (Fig 4) is standard factory-installed equipment on this model. Refer to Battery System Specifications for the proper specifications of the factory-installed batteries available on this model. Male post type terminals made of a soft lead material protrude from the top of the molded plastic battery case to provide the means for connecting the battery to the vehicle electrical system. The battery positive terminal post is physically larger in diameter than the negative terminal post to ensure proper battery connection. 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 identification confirmation. Refer to Battery Cables for more information on the battery cables that connect the battery to the vehicle electrical system.
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 an electrolyte.
The factory-installed battery has a built-in test indicator (hydrometer). The color visible in the sight glass of the indicator will reveal the battery condition. Refer to Standard Procedures for the proper built-in indicator test procedures. The factory-installed low-maintenance battery has non-removable battery cell caps. Water cannot be added to this battery The battery is not sealed and has vent holes in the cell caps. 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. Rapid loss of electrolyte can be caused by an overcharging condition. Be certain to diagnose the charging system before returning the vehicle to service. (Refer to ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING).
Fig. 17 Battery Hold Downs - Typical:
BATTERY HOLDDOWN
The battery hold down hardware (Fig. 17) includes two bolts, two U-nuts and a hold down strap. The battery hold down bracket consists of a formed steel rod with a stamped steel angle bracket welded to each end. The hold down bracket assembly is then plastic-coated for corrosion protection. Models equipped with the optional diesel engine have a second battery installed in a second battery tray on the right side of the engine compartment. The hold down hardware for the right side battery is mirror image of the hold down hardware used for the left side battery.
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.
CAUTION: Never operate a vehicle without a battery holddown device properly installed. Damage to the vehicle, components and battery could result.
Fig. 19 Battery Cables - Typical:
BATTERY CABLE
The battery cables (Fig. 19) 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 Refer to Wiring Diagrams for the location of the proper battery cable wire gauge information.
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 positive cable wire harness or the battery negative cable wire harness, which may include portions of the wiring circuits for the generator and other components on some models.
The battery cables connect the battery terminal posts to the vehicle electrical system. These cables also provide a return path 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 ends of the battery cable wires opposite the female battery terminal clamps provide secure and reliable connection of the battery to the vehicle electrical system.
Gasoline Engine Battery Cables
Gasoline engine models feature a stamped brass clamping type female battery terminal crimped onto one end of the battery cable wire and then solder-dipped. A square headed pinch-bolt and hex nut are installed at the open end of the female battery terminal clamp. The battery positive cable also includes a red molded rubber protective cover for 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 positive cable terminal clamp is crimped 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 crimped 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 front of the left engine cylinder head. The other wire has an eyelet terminal that connects the battery negative cable to the vehicle body through a ground screw on the left front fender inner shield, just ahead of the battery. An additional ground wire with two eyelet terminals is used to provide ground to the vehicle frame. One eyelet terminal of this ground wire is installed under the head of the battery negative cable terminal clamp pinch-bolt, and the other eyelet terminal is secured with a ground screw to the outer surface of the left frame rail, below the battery.
Diesel Engine Battery Cables
Diesel engine models feature a clamping type female battery terminal made of soft lead 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. The pinch-bolt on the left side battery positive cable female terminal clamp also has a stud extending from the head of the bolt. 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 left battery positive cable terminal clamp is die cast onto the ends of two wires. One wire has an eyelet terminal that connects the left 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 left battery positive cable to the B(+) terminal stud of the engine starter motor solenoid.
The right battery positive cable terminal clamp is die cast onto the end of a single wire. The eyelet terminal on the other end of the right battery positive cable is connected to the stud on the pinch-bolt of the left battery positive cable terminal clamp. This stud also provides a connection point for the eyelet terminals from the fuel heater relay and intake air heater relay jumper harness take outs. All of these eyelet terminals are secured to the left battery positive cable terminal clamp pinch-bolt stud with a single hex nut.
The left battery negative cable terminal clamp is die cast onto the ends of two wires. One wire has an eyelet terminal that connects the left battery negative cable to the vehicle powertrain through a ground screw on the left side of the engine block, below the power steering and vacuum pumps. The other wire has an eyelet terminal that connects the left battery negative cable to the vehicle body through a ground screw on the left front fender inner shield, just ahead of the left battery. An additional ground wire with two eyelet terminals is used to provide ground to the vehicle frame. One eyelet terminal of this ground wire is installed under the nut of the left battery negative cable terminal clamp pinch-bolt, and the other eyelet terminal is secured with a ground screw to the outer surface of the left frame rail, below the left battery.
The right battery negative cable terminal is also die cast onto the ends of two wires. One wire has an eyelet terminal that connects the right battery negative cable to the vehicle powertrain through a ground screw on the right side of the engine block, just forward of the right engine mount. The other wire has an eyelet terminal that connects the right battery negative cable to the vehicle body through a ground screw on the right front fender inner shield, just behind the right battery.
Fig. 25 Battery Tray - Typical:
BATTERY TRAY
The battery is mounted in a molded plastic tray (Fig. 25) with an integral support located in the left front corner of the engine compartment. A U-nut held in a molded formation on each side of the battery tray provides anchor points for the battery hold down bolts. The battery tray is secured on the outboard side to the inner fender shield by two hex screws with washers, and from underneath the integral battery tray support is secured to the left front wheelhouse inner panel by two stud plates. Each stud plate has two studs and is secured by two nuts with washers. The stud plate that secures the front of the battery tray support to the wheelhouse inner panel is installed through the wheelhouse panel from the top. The stud plate that secures the rear of the battery tray support to the wheelhouse inner panel is installed through the wheelhouse panel from the bottom.
A hole in the bottom of the battery tray is fitted with a battery temperature sensor (Refer to ELECTRICAL/CHARGING/BATTERY TEMPERATURE SENSOR - DESCRIPTION). Models that are equipped with an optional vehicle speed control system have the speed control servo secured to the integral battery tray support.
Models that are equipped with the diesel engine option have a second battery tray located in the right front corner of the engine compartment. This second battery tray and its mounting are mirror image of the standard equipment left battery tray. However, the right battery tray and support have no provisions for a battery temperature sensor or a speed control servo mounting bracket.
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 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.