Battery: Description and Operation

Battery Construction:

Test Indicator:

Built-In Test Indicator Sight Glass:

INTRODUCTION
The battery stores, stabilizes, and produces electrical current to operate various electrical systems in the vehicle. The determination of whether a battery is good or bad is made by the battery's ability to accept a charge. It also must produce high amperage current output over an extended period to be able to start the vehicle, The capability of the battery to store electrical current comes from a chemical reaction. This reaction takes place between the sulfuric acid electrolyte solution and the lead ± plates in each cell of the battery. As the battery discharges, the plates react with the acid from the electrolyte. When the charging system charges the battery, the water is converted to sulfuric acid in the battery. The amount of acid, specific gravity in the electrolyte can be measured with a hydrometer. The factory installed battery is equipped with a built in hydrometer as a test indicator to help in determining the battery's state of charge. The factory installed battery also is sealed. Water cannot and should not be added.

Battery Location:

The battery is vented to release gases that is created when the battery is being charged and discharged. The battery top, side terminals and battery cables should be cleaned when under hood maintenance is performed.

WARNING: DO NOT ASSIST BOOST CHARGE, OR LOAD TEST BATTERY WHEN ELECTROLYTE LEVEL IS BELOW THE TOP OF THE PLATES. PERSONAL INJURY MAY OCCUR.

The battery is located behind the left rear wheel well splash shield.

SYSTEM OPERATION
Causes of Battery Discharging
It is normal to have a small 5 to 30 milliamperes continuous electrical draw from the battery. This draw will take place with the ignition in the OFF position, and the courtesy, and other lights OFF. The continuous draw is due to various electronic features or accessories that require electrical current with the ignition OFF to function properly. When a vehicle is not used over an extended period approximately 20 days the battery negative cable should be disconnected. Disconnection of this cable will help prevent battery discharging.

Test Indicator
The test indicator is a hydrometer viewed through a sight glass, it is built into the top of the battery case. This provides visual information for battery condition. It is important when using the Test Indicator that the battery be level and have a clean tool to see the correct indications. A light may be required to view the Indicator.

WARNING: DO NOT USE OPEN FLAME NEAR BATTERY BECAUSE EXPLOSIVE GASES FORM ABOUT THE BATTERY.

The built in test hydrometer measures the specific gravity of the electrolyte. Specific Gravity (SG) of the electrolyte will show state of charge voltage. The test indicator WILL NOT show cranking capacity of the battery. Refer to Battery Load. Look into the sight glass and note the color of the indicator. Refer to the following description of colors:
^ GREEN = State of Charge 75 to 100 Percent.
The battery is adequately charged for further testing and may be returned to use. If the vehicle will not crank for a maximum 15 seconds, refer to Battery Load Test for more information.
^ BLACK OR DARK = State of Charge 0 to 75 Percent
The battery is INADEQUATELY charged and must be charged until green dot is visible, (12.4 Volts or greater) before the battery is tested or returned to use. Refer to Causes of Battery Discharging.
^ YELLOW OR BRIGHT COLOR = Battery must be replaced

WARNING: DO NOT CHARGE, ASSIST BOOST OR LOAD TEST THE BATTERY WHEN YELLOW OR BRIGHT COLOR DOT IS VISIBLE. PERSONAL INJURY MAY OCCUR.

A yellow or bright color dot shows electrolyte level in battery is below the test indicator. Water cannot be added to a maintenance free battery The battery must be replaced. A low electrolyte level may be caused by an over charging condition. Refer to Generator Test.

Charging Time Required

WARNING: NEVER EXCEED 20 AMPS WHEN CHARGING A COLD -1° C (30° F) BATTERY. PERSONAL INJURY MAY RESULT.

The time required to charge a battery will vary depending upon the following factors.

Battery Charging Timetable:

Size of Battery
A completely discharged large heavy-duty battery may require more recharging time than a completely discharged small capacity battery. Refer to Battery Charging Timetable.

Temperature
A longer time will be needed to charge a battery at -18° C (0° F) than at 27° C (80° F). When a fast charger is connected to a cold battery, current accepted by battery will be very low at first. In time, the battery will accept a higher rate as battery temperature warms.

Charger Capacity
A charger which can supply only five amperes will require a much longer period of charging than a charger that can supply 20 amperes or more.

State of Charge
A completely discharged battery requires more charging time than a partially charged battery. Electrolyte is nearly pure water in a completely discharged battery. At first, the charging current amperage will be low. As water is converted back to sulfuric acid inside the battery, the current amp rate will rise. Also, the specific gravity of the electrolyte will rise, bringing the green ball into view at approximately 75 percent state-of-charge.

Ignition Off Draw (IOD)
A normal electrical system will draw from 5 to 30 milliamperes from the battery. This is with the ignition in the OFF position, and all non-ignition controlled circuits in proper working order. The amount of IOD will depend on body model and electrical components. A vehicle that has not been operated for an extended period of approximately 20 days may discharge the battery to an inadequate level. In this case, the battery negative cable should be disconnected.

If the IOD is over 30 milliamperes, the defect must be found and corrected before condemning the battery. Usually, the battery can be charged and returned to service. Refer to the Battery Charging Timetable Chart.