GM Service Manual Online
For 1990-2009 cars only

When it is necessary to charge the battery, the following conditions must be observed.

    • Use a constant voltage power supply with an end charge voltage of 16.0 volts direct current (VDC) and equipped with a voltmeter that is accurate within 1%.
    • If more than one battery is to be charged, the batteries should be connected in parallel with each other; positive to positive (+ to +) and negative to negative (- to -).
    • Ambient (surrounding) temperature should be 15 to 38°C (60 to 100°F). A battery that is extremely cold may not accept current for several hours after charging has begun.
    • The charging area should be well ventilated.
    • Do not charge the battery if the built-in hydrometer is clear or light yellow. Replace the battery if this condition is discovered. Refer to Battery Hydrometer Displays Dark or Yellow Dot or Battery Hydrometer Displays Yellow Dot .
    • Do not charge the battery if the electrolytes are frozen.
    • If the battery feels as hot as 52°C (125°F) or hotter, or if violent gassing or spewing of electrolyte through the vent holes occurs, discontinue charging or reduce the charging rate.

Charging Procedure

  1. Batteries with a built-in hydrometer showing a green dot do not require charging unless they have just been discharged (by cranking the engine).

  2. Object Number: 167894  Size: SH
  3. Connect the battery charger cables to the positive (+) (4) and the negative (-) battery terminals (2). Make sure all charger cable-to-battery terminal connections are clean and tight.
  4. Important: Do not use the charge settings for jump starting the vehicles.

  5. Charge the battery using the charge setting for 12 VDC batteries that gives the highest charge rate to the battery. Refer to the battery charger manufacturer's instructions.
  6. Charge the battery until the green dot appears in the hydrometer. Check the battery every half-hour. The battery may need to be tipped or shaken gently for the green dot to appear.
  7. After charging, the battery should be tested. Refer to Battery Load Test .

Charging Time Required

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

    • Size of battery -- A completely discharged, large (heavy duty) battery requires more than twice the recharging time as a completely discharged small (passenger car) battery.
    • Temperature -- A longer time will be 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 will be very low at first. The battery will accept a higher rate of current as it warms.
    • Charger capacity -- A charger which can supply only 5 amperes will require a much longer charging period than a charger that can supply 30 amperes or more.
    • State-of-charge -- A completely discharged battery requires more than twice as much charge as a half charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the current accepted by the battery is very low at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current will also increase.
    • Any battery discharged by parasitic load, and then allowed to stand in this condition for a period of time, may not accept charge readily. However, if recharged long enough, many batteries will return to a good usable condition.
    • If the battery remains in an extremely discharged condition for a prolonged period, it can become permanently damaged. This damage can be accelerated by low temperatures. Batteries which are extremely discharged can freeze at temperatures as high as -6°C (20°F) and be permanently damaged.
        To prevent battery damage and recharge problems, vehicles which are not going to be in service within a 20 day period should have the battery negative (-) cable disconnected to remove the constant drain on the battery. If this is not possible, the battery should be recharged periodically every 20 to 45 days until the green dot is visible in the hydrometer or an open circuit voltage of 12.4 VDC is obtained.