Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

Notice: Do not use the boost, jump start, crank, or an equivalent setting that may be available on the battery charger for prolonged charging of the battery. Using such settings may damage the battery due to overheating, excessive gassing, or spewing of electrolyte from the vents.

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

1. The size of the battery -- A completely discharged, large, heavy-duty battery requires more than twice the recharging time as a completely discharged, smaller capacity battery.
2. The temperature -- A longer time is needed to charge any battery at -18°C (0°F) than at 27°C (80°F). When a fast charger is connected to a cold battery, the current accepted by the battery is very low at first. As the battery warms, the battery accepts current at a higher rate.
3. The charging capacity -- The higher the charger amperage, the faster the battery will charge.
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 ST-1201 Battery Side Terminal Adapter (Pair)

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

Notice: Do not use the boost, jump start, crank, or an equivalent setting that may be available on the battery charger for prolonged charging of the battery. Using such settings may damage the battery due to overheating, excessive gassing, or spewing of electrolyte from the vents.

1. Do not charge a battery with a clear or light yellow hydrometer. Replace the battery. Refer to Battery Replacement .
2. Do not charge a battery with a green hydrometer dot unless it has just been discharged, such as in cranking the engine.
3. When charging side-terminal batteries while on-vehicle, use the following procedure:

3.1.	Turn OFF the charger.

3.2.	Connect the charger positive lead to the positive booster cable terminal.

3.3.	Connect the negative charger lead to a solid engine ground.




4. When charging side-terminal batteries out of the vehicle, install a terminal adapter kit (AC Delco P/N ST-1201, GM P/N 123033040, or equivalent). The terminals must be tight against the lead terminals of the battery to prevent excessive resistance between the adapters and the terminals.
5. Make sure all the battery terminals are clean and tight.
6. A 40-50 ampere charging level is recommended for a discharged battery.
7. Charge the battery until the hydrometer has a green dot.
8. Inspect the battery every half hour after starting the battery charger.
9. Tap the hydrometer lightly to dislodge any air bubbles. The bubbles can cause a false indication.
10. Test the battery after charging. Refer to Battery Check .