1. Use a charger, with an end voltage of 16 V, equipped with a voltmeter that is accurate to within 1 percent.
2. The ambient temperature should be 15-38°C (60-100°F). A battery that is extremely cold will not accept measurable current for several hours after starting the charger.
3. The charging area should be well ventilated.
4. Do not charge the battery when the built in hydrometer is clear or yellow (3). Replace the battery if there is a cranking problem.
5. Do not charge a battery that appears to be frozen, replace it.
6. Batteries showing a green dot in the hydrometer (1) do not need to be charged unless they have just been discharged (such as cranking the engine).

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 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 it 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 battery terminal.

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




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

Tighten
Tighten the battery side terminal adapters to 15 N·m (11 lb ft).

4. Make sure 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 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 to dislodge any air bubbles. The bubbles may cause a false indication.
9. After charging, load test the battery.