GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Montana 🢒 Engine 🢒 Engine Electrical 🢒 Battery Charging

Follow these basic rules when charging a battery:

Caution: Before servicing any electrical component, the ignition and start switch must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause 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.

    • 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).
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Object Number: 181056 Size: SH
  • Batteries showing a black or dark dot in the hydrometer (2) can be charged.
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  • Do not charge the battery (3). Replace the battery if the built in hydrometer is clear or light yellow and there is a cranking problem. A clear or light yellow hydrometer indicates a low electrolyte level in the battery.
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  • To keep charge time to a minimum, use a charger capable of an end voltage of at least 16 volts and equipped with a voltmeter that is accurate to within 1 percent.
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  • Do not use boost, jump start, crank, or an equivalent setting for prolonged charging of the battery. Undesirable and potentially dangerous spewing of gasses or electrolyte through the vent holes may occur.
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  • 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.
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  • The charging area should be well ventilated.
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  • Do not charge a battery that appears to be frozen. Replace any frozen battery. Refer to Battery Replacement .
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  • Check the battery being charged every 30 minutes to avoid overcharging the battery.
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  • If during charging the battery feels hot, 52° C (125° F), or if gassing or spewing of the electrolyte through the vent holes occurs, discontinue the charging or reduce the charging rate.
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  • Stop charging within one hour after the green dot appears in the hydrometer.

    • Charging Time Required

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

        • 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.
        • 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.
        • The charging capacity -- The higher the charger amperage, the faster the battery will charge.
        • 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.

    Charging Procedure

    Tools Required

    GM P/N 12303040 ST-1201 Battery Side Terminal Adapters (Pair)

    Caution: Before servicing any electrical component, the ignition and start switch must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause 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.


      Object Number: 42433 Size: SH
    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:
      4. 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, useGM P/N 12303040 . 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. Load test the battery after charging. Refer to Battery Inspection/Test .