MICRO 420 BATTERY TESTER
The Micro 420 automotive battery tester is designed to help the dealership technicians diagnose the cause of a defective battery. Follow the instruction manual supplied with the tester to properly diagnose a vehicle. If the instruction manual is not available refer to STANDARD PROCEDURE , which includes the directions for using the Micro 420 battery tester.
| BATTERY SYSTEM DIAGNOSIS | ||
|---|---|---|
| CONDITION | POSSIBLE CAUSES | CORRECTION |
| THE BATTERY SEEMS WEAK OR DEAD WHEN ATTEMPTING TO START THE ENGINE. | 1. The electrical system ignition-off draw is excessive. | 1. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - IGNITION-OFF DRAW TEST) for the proper test procedures. Repair the excessive ignition-off draw, as required. |
| 2. The charging system is inoperative. | 2. Determine if the charging system is performing to specifications. (Refer to ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) for additional charging system diagnosis and testing procedures. Repair the inoperative charging system, as required. | |
| 3. The battery is discharged. | 3. Determine the battery state-of-charge using the Micro 420 battery tester. Refer to STANDARD PROCEDURE for additional test procedures. Charge the inoperative battery, as required. | |
| 4. The battery terminal connections are loose or corroded. | 4. (Refer to ELECTRICAL/BATTERY SYSTEM/CABLES - DIAGNOSIS AND TESTING) for the proper battery cable diagnosis and testing procedures. Clean and tighten the battery terminal connections, as required. | |
| 5. The battery has an incorrect size or rating for this vehicle. | 5. (Refer to ELECTRICAL/BATTERY SYSTEM - SPECIFICATIONS) for the proper size and rating. Replace an incorrect battery, as required. | |
| 6. The battery is inoperative. | 6. Test the battery using the Micro 420 battery tester. Refer to STANDARD PROCEDURE for additional test procedures. Replace the inoperative battery, as required. | |
| 7. The starting system is inoperative. | 7. Determine if the starting system is performing to specifications. (Refer to ELECTRICAL/STARTING - DIAGNOSIS AND TESTING) for the proper starting system diagnosis and testing procedures. Repair the inoperative starting system, as required. | |
| 8. The battery is physically damaged. | 8. Inspect the battery for loose terminal posts or a cracked and leaking case. Replace the damaged battery, as required. | |
| THE BATTERY STATE OF CHARGE CANNOT BE MAINTAINED. | 1. The battery has an incorrect size or rating for this vehicle. | 1. (Refer to ELECTRICAL/BATTERY SYSTEM - SPECIFICATIONS) for the proper specifications. Replace an incorrect battery, as required. |
| 2. The battery terminal connections are loose or corroded. | 2. (Refer to ELECTRICAL/BATTERY SYSTEM/CABLES - DIAGNOSIS AND TESTING) for the proper cable diagnosis and testing procedures. Clean and tighten the battery terminal connections, as required. | |
| 3. The electrical system ignition-off draw is excessive. | 3. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - IGNITION-OFF DRAW TEST) for the proper test procedures. Repair the inoperative electrical system, as required. | |
| 4. The battery is inoperative. | 4. Test the battery using the Micro 420 battery tester. Refer to STANDARD PROCEDURE for additional test procedures. Replace the inoperative battery, as required. | |
| 5. The starting system is inoperative. | 5. Determine if the starting system is performing to specifications. (Refer to ELECTRICAL/STARTING - DIAGNOSIS AND TESTING) for the proper starting system diagnosis and testing procedures. Repair the inoperative starting system, as required. | |
| 6. The charging system is inoperative. | 6. Determine if the charging system is performing to specifications. (Refer to ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) for charging system diagnosis and testing procedures. Repair the inoperative charging system, as required. | |
| 7. Electrical loads exceed the output of the charging system. | 7. Inspect the vehicle for aftermarket electrical equipment which might cause excessive electrical loads. | |
| 8. Slow driving or prolonged idling with high-amperage draw loads in use. | 8. Advise the vehicle operator, as required. | |
| THE BATTERY WILL NOT ACCEPT A CHARGE. | 1. The battery is inoperative. | 1. Test the battery using the Micro 420 battery tester. Charge or replace the inoperative battery, as required. |
CLEANING
The following information details the recommended cleaning procedures for the battery and related components. In addition to the maintenance schedules found in this service information and the owner's manual, it is recommended that these procedures be performed any time the battery or related components must be removed for vehicle service.
Scheme 12
Scheme 13
- Clean the battery cable terminal clamps of all corrosion. Remove any corrosion using a wire brush or a post and terminal cleaning tool, and a sodium bicarbonate (baking soda) and warm water cleaning solution. (Scheme 12) 1 - TERMINAL BRUSH 2 - BATTERY CABLE
- Clean the battery tray and battery holddown hardware of all corrosion. Remove any corrosion using a wire brush and a sodium bicarbonate (baking soda) and warm water cleaning solution. Paint any exposed bare metal.
- If the removed battery is to be reinstalled, clean the outside of the battery case and the top cover with a sodium bicarbonate (baking soda) and warm water cleaning solution using a stiff bristle parts cleaning brush to remove any acid film. (Scheme 13) Rinse the battery with clean water. Ensure that the cleaning solution does not enter the battery cells through the vent holes. If the battery is being replaced, refer to «SPECIFICATIONS»(ref-248889-S07056995212007022700000) for the factory-installed battery specifications. Confirm that the replacement battery is the correct size and has the correct ratings for the vehicle. 1 - CLEANING BRUSH 2 - WARM WATER AND BAKING SODA SOLUTION 3 - BATTERY
- Clean the battery thermowrap with a sodium bicarbonate (baking soda) and warm water cleaning solution using a soft bristle parts cleaning brush to remove any acid film.
- Clean any corrosion from the battery terminal posts with a wire brush or a post and terminal cleaner, and a sodium bicarbonate (baking soda) and warm water cleaning solution. (Scheme 14)
Scheme 14
| 1 - TERMINAL BRUSH |
|---|
| 2 - BATTERY CABLE |
| 3 - BATTERY |
The Micro 420 automotive battery tester is designed to help the dealership technicians diagnose the cause of a defective battery. Follow the instruction manual supplied with the tester or (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING THE MICRO 420 BATTERY TESTER) to properly diagnose a vehicle
| WARNING | IF THE BATTERY SHOWS SIGNS OF FREEZING, LEAKING OR LOOSE POSTS, DO NOT TEST, ASSIST-BOOST, OR CHARGE. THE BATTERY MAY ARC INTERNALLY AND EXPLODE. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT. |
| WARNING | EXPLOSIVE HYDROGEN GAS FORMS IN AND AROUND THE BATTERY. DO NOT SMOKE, USE FLAME, OR CREATE SPARKS NEAR THE BATTERY. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT. |
| WARNING | THE BATTERY CONTAINS SULFURIC ACID, WHICH IS POISONOUS AND CAUSTIC. AVOID CONTACT WITH THE SKIN, EYES, OR CLOTHING. IN THE EVENT OF CONTACT, FLUSH WITH WATER AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT OF THE REACH OF CHILDREN. |
A battery that will not accept a charge is inoperative, and must be replaced. Further testing is not required. A fully-charged battery must be tested to determine its cranking capacity. A battery that is fully-charged, but does not pass the Micro 420 or load test, is inoperative and must be replaced.
Note. Completely discharged batteries may take several hours to accept a charge. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE) for the proper battery charging procedures.
SPIRAL PLATE BATTERY CHARGING
Vehicles equipped with a diesel engine utilize a unique spiral plate battery. This battery has a maximum charging voltage that must not be exceeded in order to restore the battery to its full potential, failure to use the following spiral plate battery charging procedure could result in damage to the battery or personal injury.
Battery charging is the means by which the battery can be restored to its full voltage potential. A battery is fully-charged when
- Micro 420 battery tester indicates battery is OK.
- Open-circuit voltage of the battery is 12.65 volts or above.
- Battery passes Load Test multiple times.
| WARNING | IF THE BATTERY SHOWS SIGNS OF FREEZING, LEAKING, LOOSE POSTS OR LOW ELECTROLYTE LEVEL, DO NOT TEST, ASSIST-BOOST, OR CHARGE. THE BATTERY MAY ARC INTERNALLY AND EXPLODE. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT. |
| CAUTION | Always disconnect and isolate the battery negative cable before charging a battery. Charge the battery directly at the battery terminals. Do not exceed 14.4 volts while charging a battery. |
| CAUTION | The battery should not be hot to the touch. If the battery feels hot to the touch, turn off the charger and let the battery cool before continuing the charging operation. Damage to the battery may result. |
After the battery has been charged to 12.6 volts or greater, perform a load test to determine the battery cranking capacity. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING THE MICRO 420 BATTERY TESTER) for the proper battery test procedures. If the battery passes a load test, return the battery to service. If the battery will not pass a load test, it is inoperative and must be replaced.
Clean and inspect the battery hold downs, tray, terminals, posts, and top before completing battery service. (Refer to ELECTRICAL/BATTERY SYSTEM - CLEANING) for the proper battery system cleaning procedures, and (Refer to ELECTRICAL/BATTERY SYSTEM - INSPECTION) for the proper battery system inspection procedures.
CHARGING A COMPLETELY DISCHARGED BATTERY - SPIRAL PLATE BATTERY
The following procedure should be used to recharge a completely discharged battery. Unless this procedure is properly followed, a good battery may be needlessly replaced.
Scheme 15
- Measure the voltage at the battery posts with a voltmeter, accurate to 1/10 (0.10) volt. (Scheme 15) «(Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - REMOVAL)»(ref-248889-S29572206352007022700000) for instructions on how to access the battery. If the reading is below ten volts, the battery charging current will be low. It could take several hours before the battery accepts a current greater than a few milliamperes. Such low current may not be detectable on the ammeters built into many battery chargers.
- Disconnect and isolate the battery negative cable. Connect the battery charger leads. Some battery chargers are equipped with polarity-sensing circuitry. This circuitry protects the battery charger and the battery from being damaged if they are improperly connected. If the battery state-of-charge is too low for the polarity-sensing circuitry to detect, the battery charger will not operate. This makes it appear that the battery will not accept charging current. See the instructions provided by the manufacturer of the battery charger for details on how to bypass the polarity-sensing circuitry.
- Battery chargers vary in the amount of voltage and current they provide. The amount of time required for a battery to accept measurable charging current at various voltages is shown in the Charge Rate Table. If the charging current is still not measurable at the end of the charging time, the battery is inoperative and must be replaced. If the charging current is measurable during the charging time, the battery may be good and the charging should be completed in the normal manner.
| SPIRAL-PLATE BATTERY CHARGE RATE TABLE | |
|---|---|
| Voltage | Minutes |
| 14.4 volts maximum | Up to 10 minutes |
| 13.0 to 14 volts | Up to 20 minutes |
| 12.9 volts or less | Up to 30 minutes |
CHARGING TIME REQUIRED
The time required to charge a battery will vary, depending upon the following factors
- Battery Capacity - A completely discharged heavy-duty battery requires twice the charging time of a small capacity battery.
- Temperature - A longer time will be needed to charge a battery at -18° C (0° F) than at 27° C (80° F). When a fast battery charger is connected to a cold battery, the current accepted by the battery will be very low at first. As the battery warms, it will accept a higher charging current rate (amperage).
- Charger Capacity - A battery charger that supplies only five amperes will require a longer charging time. A battery charger that supplies eight amperes will require a shorter charging time.
- State-Of-Charge - A completely discharged battery requires more charging time than a partially discharged battery. Electrolyte is nearly pure water in a completely discharged battery. At first, the charging current (amperage) will be low. As the battery charges, the specific gravity of the electrolyte will gradually rise.
The Battery Charging Time Table gives an indication of the time required to charge a typical battery at room temperature based upon the battery state-of-charge and the charger capacity.
| SPIRAL-PLATE BATTERY CHARGING TIME TABLE | ||
|---|---|---|
| Charging Amperage | 5 Amps | 8 Amps |
| Open Circuit Voltage | Hours Charging @ 21° C (70° F) | |
| 12.25 to 12.49 | 6 hours | 3 hours |
| 12.00 to 12.24 | 10 hours | 5 hours |
| 10.00 to 11.99 | 14 hours | 7 hours |
| Below 10.00 | 18 hours | 9 hours |
CONVENTIONAL BATTERY CHARGING
Vehicles equipped with a diesel engine utilize a unique spiral plate battery. This battery has a maximum charging voltage that must be used in order to restore the battery to its full potential, failure to use the spiral plate battery charging procedure could result in damage to the battery or personal injury.
Battery charging is the means by which the battery can be restored to its full voltage potential. A battery is fully-charged when
- Micro 420 battery tester indicates battery is OK.
- Open-circuit voltage of the battery is 12.65 volts or above.
- Battery passes Load Test multiple times.
| WARNING | IF THE BATTERY SHOWS SIGNS OF FREEZING, LEAKING, LOOSE POSTS, DO NOT TEST, ASSIST-BOOST, OR CHARGE. THE BATTERY MAY ARC INTERNALLY AND EXPLODE. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT. |
| WARNING | EXPLOSIVE HYDROGEN GAS FORMS IN AND AROUND THE BATTERY. DO NOT SMOKE, USE FLAME, OR CREATE SPARKS NEAR THE BATTERY. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT. |
| WARNING | THE BATTERY CONTAINS SULFURIC ACID, WHICH IS POISONOUS AND CAUSTIC. AVOID CONTACT WITH THE SKIN, EYES, OR CLOTHING. IN THE EVENT OF CONTACT, FLUSH WITH WATER AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT OF THE REACH OF CHILDREN. |
| WARNING | IF THE BATTERY IS EQUIPPED WITH REMOVABLE CELL CAPS, BE CERTAIN THAT EACH OF THE CELL CAPS IS IN PLACE AND TIGHT BEFORE THE BATTERY IS RETURNED TO SERVICE. PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT FROM LOOSE OR MISSING CELL CAPS. |
| CAUTION | Always disconnect and isolate the battery negative cable before charging a battery. Do not exceed sixteen volts while charging a battery. Damage to the vehicle electrical system components may result. |
| CAUTION | Battery electrolyte will bubble inside the battery case during normal battery charging. Electrolyte boiling or being discharged from the battery vents indicates a battery overcharging condition. Immediately reduce the charging rate or turn off the charger to evaluate the battery condition. Damage to the battery may result from overcharging. |
| CAUTION | The battery should not be hot to the touch. If the battery feels hot to the touch, turn off the charger and let the battery cool before continuing the charging operation. Damage to the battery may result. |
After the battery has been charged to an open-circuit voltage reading of 12.4 volts or greater, retest the battery with the Micro 420 tester or perform a load test to determine the battery cranking capacity. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE) for the proper battery load test procedures. If the battery passes a load test, return the battery to service. If the battery will not pass a load test, it is inoperative and must be replaced.
Clean and inspect the battery hold downs, tray, terminals, posts, and top before completing battery service. (Refer to ELECTRICAL/BATTERY SYSTEM - CLEANING) for the proper battery system cleaning procedures, and (Refer to ELECTRICAL/BATTERY SYSTEM - INSPECTION) for the proper battery system inspection procedures.
CHARGING A COMPLETELY DISCHARGED CONVENTIONAL BATTERY
The following procedure should be used to recharge a completely discharged battery. Unless this procedure is properly followed, a good battery may be needlessly replaced.
Scheme 16
- Measure the voltage at the battery posts with a voltmeter, accurate to 1/10 (0.10) volt. (Scheme 15) If the reading is below ten volts, the battery charging current will be low. It could take some time before the battery accepts a current greater than a few milliamperes. Such low current may not be detectable on the ammeters built into many battery chargers.
- Disconnect and isolate the battery negative cable. Connect the battery charger leads. Some battery chargers are equipped with polarity-sensing circuitry. This circuitry protects the battery charger and the battery from being damaged if they are improperly connected. If the battery state-of-charge is too low for the polarity-sensing circuitry to detect, the battery charger will not operate. This makes it appear that the battery will not accept charging current. See the instructions provided by the manufacturer of the battery charger for details on how to bypass the polarity-sensing circuitry.
- Battery chargers vary in the amount of voltage and current they provide. The amount of time required for a battery to accept measurable charging current at various voltages is shown in the Charge Rate Table. If the charging current is still not measurable at the end of the charging time, the battery is inoperative and must be replaced. If the charging current is measurable during the charging time, the battery may be good and the charging should be completed in the normal manner.
| CONVENTIONAL BATTERY CHARGE RATE TABLE | |
|---|---|
| Voltage | Minutes |
| 16.0 volts maximum | Up to 10 min. |
| 14.0 to 15.9 volts | Up to 20 min. |
| 13.9 volts or less | Up to 30 min. |
The time required to charge a battery will vary, depending upon the following factors
- Battery Capacity - A completely discharged heavy-duty battery requires twice the charging time of a small capacity battery.
- Temperature - A longer time will be needed to charge a battery at -18° C (0° F) than at 27° C (80° F). When a fast battery charger is connected to a cold battery, the current accepted by the battery will be very low at first. As the battery warms, it will accept a higher charging current rate (amperage).
- Charger Capacity - A battery charger that supplies only five amperes will require a longer charging time. A battery charger that supplies twenty amperes or more will require a shorter charging time.
- State-Of-Charge - A completely discharged battery requires more charging time than a partially discharged battery. Electrolyte is nearly pure water in a completely discharged battery. At first, the charging current (amperage) will be low. As the battery charges, the specific gravity of the electrolyte will gradually rise.
The Conventional Battery Charging Time Table gives an indication of the time required to charge a typical battery at room temperature based upon the battery state-of-charge and the charger capacity.
| CONVENTIONAL BATTERY CHARGING TIME TABLE | |||
|---|---|---|---|
| Charging Amperage | 5 Amps | 10 Amps | 20 Amps |
| Open Circuit Voltage | Hours Charging @ 21° C (70° F) | ||
| 12.25 to 12.49 | 6 hours | 3 hours | 1.5 hours |
| 12.00 to 12.24 | 10 hours | 5 hours | 2.5 hours |
| 10.00 to 11.99 | 14 hours | 7 hours | 3.5 hours |
| Below 10.00 | 18 hours | 9 hours | 4.5 hours |
CHECKING BATTERY ELECTROLYTE LEVEL
The following procedure can be used to check the electrolyte level in a low-maintenance lead-acid battery.
Scheme 17
- Unscrew and remove the battery cell caps with a flat-bladed screw driver. see scheme 10 1 - BATTERY CELL CAP 2 - BATTERY CASE WARNING: NEVER PUT YOUR FACE NEAR A GASSING, HOT OR SWELLED BATTERY. SERIOUS PERSONAL INJURY MAY RESULT.
- Wearing safety glasses, look through the battery cell cap holes to determine the level of the electrolyte in the battery. The electrolyte should be above the hooks inside the battery cells. (Scheme 17) 1 - TOP OF BATTERY 2 - HOOK INSIDE BATTERY CELLS
- Add only distilled water until the electrolyte is above the hooks inside the battery cells. (Scheme 17)
Scheme 18
Always use the Micro 420 Instruction Manual that was supplied with the tester as a reference. If the Instruction Manual is not available the following procedure can be used
| WARNING | ALWAYS WEAR APPROPRIATE EYE PROTECTION AND USE EXTREME CAUTION WHEN WORKING WITH BATTERIES. |
BATTERY CABLES
A voltage drop test will determine if there is excessive resistance in the battery cable terminal connections or the battery cable. If excessive resistance is found in the battery cable connections, the connection point should be disassembled, cleaned of all corrosion or foreign material, then reassembled. Following reassembly, check the voltage drop for the battery cable connection and the battery cable again to confirm repair.
When performing the voltage drop test, it is important to remember that the voltage drop is giving an indication of the resistance between the two points at which the voltmeter probes are attached. EXAMPLE: When testing the resistance of the battery positive cable, touch the voltmeter leads to the battery positive cable terminal clamp and to the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud. If you probe the battery positive terminal post and the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud, you are reading the combined voltage drop in the battery positive cable terminal clamp-to-terminal post connection and the battery positive cable.