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.

Important: Do not use the boost, the jump start or the crank setting for prolonged charging of batteries if the charger is equipped with these settings. Using any of these settings for a prolonged period may cause gassing or spewing of electrolyte through the vent hole.

1. Ensure that the electrolyte and the plates are at room temperature before charging the battery. An extremely cold battery may not accept the current for several hours after the charger is started.
2. Always stop charging, or reduce the charging rate, if either of the following conditions exists:

•	The battery temperature is 52°C (125°F) or higher.

•	Electrolyte spews or gasses violently through the vent holes.

3. Replace the battery when either of the following conditions exist:

•	The hydrometer is clear or yellow.

•	The battery is frozen.

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

Tools Required

GM P/N 12303040 Battery Terminal Adapters

1. Do not charge a battery with a green hydrometer dot unless it has just been discharged, such as in cranking.
2. When charging, the adapters should be snug against the battery terminals to keep resistance to a minimum.
3. Make sure all battery terminals are clean and tight.

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

4. 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.
5. Charge the battery until the hydrometer has a green dot.
6. Inspect the battery every half hour after starting the battery charger.
7. Tap the hydrometer lightly to dislodge any air bubbles. The bubbles may cause a false indication.
8. After charging, load test the battery.

1. Measure the battery voltage:

•	Measure the voltage at the battery terminals using a voltmeter.

•	A reading of less than 11 Volts indicates that the charge current is low.

•	The battery will take longer to accept a current higher than 2 milliamps.

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 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. The required battery charge time varies according to the voltage capabilities of the battery charger. Replace the battery only if the charge current is not measurable after the following charge times.

•	16 Volts or more - up to 4 hours

•	14-15.9 Volts - up to 8 hours

•	Less than 13.9 Volts - up to 16 hours

5. Reserve capacity rating:

•	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.

•	For example, if the battery has a reserve capacity rating of 90 (expressed in Ampere-hours), the battery would be recharged as follows:

-	10 Ampere charge × 9 hours = 90 Ampere hours

-	30 Ampere charge × 3 hours = 90 Ampere hours

•	If the green hydrometer dot is not visible after an Ampere-hour charge equal to twice the reserve capacity rating, replace the battery.

6. After charging, load test the battery. Refer to Battery Electrical Drain/Parasitic Load Test .