CHARGING LOW OR COMPLETELY DISCHARGED DELCO FREEDOM

Model and Year: 1987-89 CHEVROLET PASSENGER CARS AND LIGHT DUTY TRUCKS

TO: ALL CHEVROLET DEALERS

Most deeply discharged Delco Freedom batteries can be recharged when proper charging procedures are followed. To obtain maximum results and avoid needless replacement of good batteries, attention must be given to charging time, battery connections and charging procedures.

"CAUTION" Explosive Gases - All lead-acid batteries generate hydrogen gas which is explosive if ignited by spark or flame. Always shield eyes and face from battery. Do not charge or use booster cables or adjust terminal connections without proper instruction and training.

POISON - Causes Severe Burns - Battery contains sulfuric acid. Avoid contact with skin, eyes, or clothing. In event of accident, flush with water and call a physician immediately.

CHARGING TIME REOUIRED

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

Reserve Capacity of the Battery - Expressed in minutes, reserve capacity is the amount of time required for a fully charged battery at 80 degrees Farenheit, discharged at a constant rate of 25 amperes, to reach a terminal voltage of 10.5 volts. When completely discharged, a battery with a reserve capacity rating of 180 minutes requires at least twice as much recharging as a completely discharged battery with a reserve capacity rating of 90 minutes. The reserve capacity rating shown on the battery label or in test specification bulletins may be used to estimate the ampere-hours of recharge (average charging amperes multiplied by the hours of charging) that may be required. For example, a 90 minute reserve capacity battery can usually be completely recharged in 9 hours if the charging current flowing into the battery averages 10 amperes (10 X 9 = 90) . If the current averages 30 amperes, 3 hours would be sufficient (30 X 3 = 90). The actual current flow will depend on both the condition of the battery and the output capabilities of the charger. Use the average charging current as indicated by the charger ammeter to calculate ampere hours of charge.

Temperature - A longer time will be needed to charge any battery at 0 degrees Farenheit than at 80 degrees Farenheit. When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first, then in time the battery will accept a higher rate as it warms. For best results, allow cold batteries to warm to room temperature before charging.

Charger Capacity - A charger which can supply only 5 amperes will require a much longer period of charging than a charger that can supply 30 amperes or more. To minimize charging time, maximize the charging current flow by utilizing the highest charger voltage output setting for a 12 volt battery. Use of a "maintenance free" setting offered on some chargers is not necessary when charging Delco Freedom batteries, and should be avoided when another setting of the charger will give a higher voltage output. The most efficient charging will occur when a voltage of at least 16 volts can be attained.

NOTE: Do not use "boost", "jump start" or "crank" settings to charge batteries if charger is equipped with any of these settings.

State of Charge - A completely discharged battery requires more than twice as much charge as a fifty percent discharged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the current accepted by the battery will be very low at first. The charging current will increase as the acid content in the electrolyte increases.

BATTERY CONDITIONS

Adapters that provide good contact with the battery terminal pads, AC-Delco Part Number ST-1201, GM Part Number 1846855, or equivalent, are preferred for attaching chargers and test equipment to side and top terminal batteries. Clean battery terminals, adapters and charger or test equipment clamps to ensure good, low resistance connections. If the recommended adapters are not available, standard fasteners should not be used except as noted below. Failure to follow these procedures could result in damage to the battery terminals or high resistance connections that will prevent adequate charging current from reaching the battery.

Side Terminal Batteries - Two 3/8" standard thread (16 UNC) bolts (UNPLATED), at least 1.5 inches long and two standard 3/8" nuts (UNPLATED) are required. Using fingers, screw nuts onto bolts, screw bolts (with nuts) into side terminals until they bottom out then back off one full turn. Do not tighten with wrench or pliers as bolts can be driven through the case. Holding the bolt, tighten the nut until it is against the battery terminal pad. Snug nut with wrench or pliers. Do not overtighten as battery terminals could be damaged. Attach the charger clamps to the nuts. Charging current can then flow through the battery terminal pads.

Top Terminal Batteries - Two 3/8" standard thread (16 UNC) nuts, AC-Delco Part Number 7802, GM Part Number 1892161 or equivalent, are required. Charger clamps must be placed between the nuts and the battery terminal pads to ensure good contact with the lead pads. Snug nuts with wrench or pliers. Do not overtighten as battery terminals could be damaged. Charging current can then flow through the battery terminal pads.

NOTE: Good contact must be maintained between the charger and battery terminal pads to ensure maximum results. Failure to provide good contact increases charging time by approximately one third.

CHARGING PROCEDURE

The following procedure should be used to recharge a very low or completely discharged battery:

Hydrometer Check - Clean the cover, look into the built-in hydrometer and use a flashlight if necessary, to observe its reading. To ensure an accurate reading, gently tap the top of the hydrometer to dislodge any air bubbles that might cause a false green, clear or light yellow appearance.

Green Dot Visible - Any green appearance is interpreted as a "green dot" and indicates that the battery is 65 percent or above in state of charge and is ready for use or testing. A fully charged battery should have an output of 12.6 or more volts at the terminals.

Dark (Green Dot Not Visible) - Indicates the battery is below 65 percent state of charge and needs charging prior to testing.

Clear or Light Yellow - Indicates the fluid level is below the bottom of the hydrometer. This may be caused by a cracked or broken case. A battery in this condition should be replaced. Excessive or prolonged charging, excessive tipping or normal battery wearout can cause a clear or yellow light and battery replacement is required. Do not charge, test or jump start. A dark reading may be misinterpreted as a clear or light yellow reading when inspecting a Delco Freedom battery. Gently tap on the top of the hydrometer to dislodge any air bubbles that might cause a false reading. If the hydrometer remains clear or light yellow, the battery should be replaced.

Measure Terminal Voltage - Measure voltage across the battery terminals with a voltmeter. If below 11 volts, the initial charge current will be very low (milliamperes) an take several hours before the battery can accept a charging current measureable by the ammeters used on most chargers.

Connect Charger - Connect battery to charger and connect charger to power source. Set charger on high setting.

NOTE: Do not use "boost" jump start" or "crank" settings to charge batteries if charger is equipped with any of these settings.

Polarity Protection - Some chargers feature polarity protection circuitry which prevents charging unless the charger leads are connected to the battery terminals correctly. A completely discharged battery may not have enough voltage to activate this circuit, even though the leads are connected properly, making it appear as though the battery will not accept charging current. Therefore, follow the manufacturer's specific charging instructions telling how to bypass or override the circuitry so that the charger will turn on and charge a low voltage battery.

Measure Charging Voltage - Measure voltage across the battery terminals with a voltmeter, charger connected and operating. If the initial charging voltage is 16 volts or greater, it may take 4 hours before the typical charger ammeter indicates a measureable charging current for a deeply discharged battery. If the initial charging voltage is below 16 volts, as many as 8 to 16 hours may be required before charging current is noted on the ammeter. If no charging current is apparent on the charger ammeter after these times, the battery should be replaced. Measureable charging current within these times indicates that charging should be continued in the normal manner.

CHARGING VOLTAGE

Charger Voltage Hours --------------- ------ 16.0 or More Up to 4.0 Hrs. 14.0 to 15.9 Up to 8.0 Hrs. 13.9 or Less Up to 16.0 Hrs.

Monitor Battery - Monitor battery hourly for gassing or spewing of electrolyte and battery temperature above 125 degrees Farenheit as judged by feel. Adjust or temporarily halt charging as required to avoid these conditions and permit cooling. Check hydrometer hourly for green dot. Gently tap the top of the hydrometer to dislodge any trapped air bubbles that might cause a false reading. When the green dot remains in view, the battery is charged and ready for load test. If the green dot does not appear after an ampere-hour charge equal to twice the reserve capacity rating of the battery is applied, replace the battery.

Load Test - It is recommended that any battery recharged by this procedure be load tested to establish serviceability.

If the battery is in the vehicle, make sure the engine control switch is off. If there is more than one battery, check each separately.

1. Disconnect the battery cables from the terminals.

2. Install adapter AC-Delco Part Number ST-1201, or equivalent.

3. If adapters are not available, use two 3/8" standard thread (16 UNC) bolts UNPLATED, at least 1.5 inches long, and two standard 3/8" UNPLATED nuts. Finger tighten. Contact must be made through the lead pads at the face of the terminals, not through the threads of the bolt.

4. Install a voltmeter and battery load tester to the adapters.

5. Remove the surface charge from recently charged batteries by applying a 300-ampere load across the adapters for 15 seconds.

6. Do not remove the surface charge from batteries which have been in storage.

7. Turn the load off and wait 15 seconds for the battery to recover.

8. Apply the specified load indicated on the battery label. If a load test figure is not indicated, apply 50% of the cold cranking amp hour rating indicated on the battery specification tag. Observe the battery voltage after 15 seconds with the load connected, then turn off the load.

NOTE: Battery tester cable clamps should be between terminal nuts and lead pads of terminals. If not possible, load value should be 275 amperes.

9. If the battery voltage does not drop below the minimum voltage as shown in the following "Voltage and Temperature" chart, the battery is good and should be returned to service. The battery temperature must be estimated by feel and by the temperature the battery has been exposed to for the preceeding few hours. If the battery voltage drops below the minimum voltage listed, replace the battery.

VOLTAGE AND ELECTROLYTE TEMPERATURE CHART

Estimated Minimum Electrolyte Required Voltage Temperature Under 15 Sec. Load ----------- ------------------

21 degrees C (70 degrees F and Above)............9.6 10 degrees C (50 degrees F)......................9.4 -1 degree C (30 degrees F)......................9.1 10 degrees C (15 degrees F)......................8.8 -18 degrees C (O degrees F).......................8.5

BATTERY REPLACEMENT SUMMARY

Replacement of batteries under warranty should occur only when one or more of the following conditions exist:

1. Battery Hydrometer is clear or light yellow after tapping gently on the top of the hydrometer.

2. The charging current is not measurable after the specified time.

3. Physical damage.

4. Load test failure after proper charging (Reference Service Manual, Section 6D).

5. If green dot does not appear in the built in hydrometer after specified ampere hours of charge.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.