•	Use a charger, with an end voltage of 16 V, equipped with a voltmeter that is accurate to within 1 percent.

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

1. The size of the battery -- a completely discharged, heavy-duty battery requires more than twice the recharging time as a completely discharged, light duty battery.
2. The temperature -- the colder the battery, the more time it takes in order to recharge. When a fast charger is connected to a cold battery, the current accepted by the battery is very low at first. Then, as the battery warms, the battery accepts a higher rate of current.
3. The charging capacity -- the higher the charger amperage, the less time it will take to charge the battery.
4. The state-of-charge -- a completely discharged battery requires more than twice as much charge time as a half charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the battery accepts very low current at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current also increases.

Tools Required

GM P/N 12303040

Notice: Turn OFF the ignition when connecting or disconnecting the battery cables, the battery charger or the jumper cables. Failure to do so may damage the PCM or other electronic components.

1. Do not charge a battery with a green hydrometer dot unless the battery has just been discharged, such as in cranking.
2. When charging side-terminal batteries while on-vehicle, use the following procedure:

2.1.	Turn OFF the charger.

2.2.	Connect the charger positive lead to the positive cable terminal located in the engine compartment on the right side.

2.3.	Connect the negative charger lead to a solid engine ground, such as the generator mounting bracket.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.




3. When charging side-terminal batteries out of vehicle, install battery side terminal adapters.

Tighten
Tighten the battery side terminal adapters to 17 N·m (13 lb ft).

4. Ensure all battery terminals are clean and tight.
5. Best results occur when charging a battery that is at room temperature. A battery that is extremely cold may not accept the current for several hours.
6. Charge the battery until the hydrometer has a green dot.
7. Inspect the battery every half hour after starting the battery charger.
8. Tap the hydrometer lightly in order to dislodge any air bubbles. The bubbles may cause a false indication.
9. After charging, load test the battery. Refer to Battery Load Test .

Tools Required

J 39200 Digital Multimeter

Use the following procedure in order to recharge a very low or completely discharged battery. Unless the procedure is properly followed, a perfectly good battery may be needlessly replaced.

The required battery charge time varies according to the voltage capabilities of the battery charger. A charger of less than 14 volts could take up to 16 hours before the battery appears to be accepting current.

1. Measure the battery voltage at the battery terminals using the J 39200

•	A reading of less than 11 volts indicates that the initial charging will be very low.

•	It could take some time before the battery accepts a current in excess of a few milliamperes.

2. Set the battery charger on the highest setting.
3. If necessary, disable the polarity protection circuitry.

•	This circuitry, available on most chargers, prevents charging unless the charger leads are properly connected to the battery terminals.

•	A completely discharged battery may not have enough voltage in order to activate this circuitry, even though the leads are properly connected, implying that the battery will not accept a charge.

•	Most chargers have an override or a bypass function so that the charger will turn ON and charge a low voltage battery.

4. In order to determine the amount of hours the battery may need to be charged, you can make the following calculation:

•	The reserve capacity rating on the battery label is the number of ampere-hours of charge required in order to produce the green hydrometer dot.

•	After the meter on the charger starts to show current flow, note the number of amps being accepted.

•	Determine the reserve capacity of the battery.

•	Divide the reserve capacity by the number of amps shown on the meter in order to determine how many hours of charging is the battery needs.

5. When the green dot appears in the hydrometer, discontinue charging the battery.
6. If the green hydrometer dot is not visible after an ampere-hour charge equal to twice the reserve capacity rating, replace the battery. Refer to Battery Replacement .
7. After charging, load test the battery. Refer to Battery Load Test .