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  • Figure 51-1 A visual inspection on this battery shows the electrolyte level was below the plates in all cells.
  • Figure 51-2 Corrosion on a battery cable could be an indication that the battery itself is either being overcharged or is sulfated, creating a lot of gassing of the electrolyte.
  • Figure 51-3 Besides baking soda and water, a sugar-free diet soft drink can also be used to neutralize the battery acid.
  • Figure 51-4 (a) A voltage reading of 12.28 volts indicates that the battery is not fully charged and should be charged before testing.
  • Figure 51-4 (b) A battery that measures 12.6 volts or higher after the surface charge has been removed is 100% charged.
  • Chart 51-1 The estimated state of charge of a 12 volt battery after the surface charge has been removed.
  • Figure 51-5 When testing a battery using a hydrometer, the reading must be corrected if the temperature is above or below 80°F (27°C).
  • Chart 51-2 Measuring the specific gravity can detect a defective battery. A battery should be at least 75% charged before being load tested.
  • Figure 51-6 This battery has cold-cranking amperes (CCA) of 550 A, cranking amperes (CA) of 680 A, and load test amperes of 270 A listed on the top label. Not all batteries have this complete information.
  • Figure 51-7 An alternator regulator battery starter tester (ARBST) automatically loads the battery with a fixed load for 15 sec. to remove the surface charge, then removes the load for 30 sec. to allow the battery to recover, and then reapplies the load for another 15 sec. The results of the test are then displayed.
  • Figure 51-10 A conductance tester is very easy to use and has proved to accurately determine battery condition if the connections are properly made. Follow the instructions on the display exactly for best results.
  • Chart 51-3 Battery charging guideline showing the charging times that vary according to state of charge, temperature, and charging rate. It may take eight hours or more to charge a fully discharged battery. *Correct for temperature **If colder, it ’ll take longer
  • Figure 51-11 A typical industrial battery charger. Be sure that the ignition switch is in the off position before connecting any battery charger. Connect the cables of the charger to the battery before plugging the charger into the outlet. This helps prevent a voltage spike and spark that could occur if the charger happened to be accidentally left on. Always follow the battery charger manufacturer ’s instructions.
  • Chart 51-4 A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • Chart 51-4 (continued) A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • Chart 51-4 (continued) A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • Figure 51-13 A typical battery jump box used to jump start vehicles. These hand-portable units have almost made jumper cables obsolete.
  • Figure 51-16 This mini clamp-on digital multimeter is being used to measure the amount of battery electrical drain that is present. In this case, a reading of 20 mA (displayed on the meter as 00.02 A) is within the normal range of 20 to 30 mA. Be sure to clamp around all of the positive battery cable or all of the negative battery cable, whichever is easiest to get the clamp around.
  • Figure 51-17 After connecting the shut-off tool, start the engine and operate all accessories. Stop the engine and turn off everything. Connect the ammeter across the shut-off switch in parallel. Wait 20 minutes. This time allows all electronic circuits to "time out" or shut down. Open the switch—all current now will flow through the ammeter. A reading greater than specified (usually greater than 50 mA, or 0.05 A) indicates a problem that should be corrected.
  • Figure 51-18 The battery was replaced in this Acura and the radio displayed "code" when the replacement battery was installed. Thankfully, the owner had the five-digit code required to unlock the radio.
  • Figure 51-18 The battery was replaced in this Acura and the radio displayed "code" when the replacement battery was installed. Thankfully, the owner had the five-digit code required to unlock the radio.

Halderman ch051 lecture Halderman ch051 lecture Presentation Transcript

  • BATTERY TESTING AND SERVICE 51
  • Objectives
    • The student should be able to:
      • Prepare for ASE Electrical/Electronic Systems (A6) certification test content area "B" (Battery Diagnosis and Service).
      • List the precautions necessary when working with batteries.
      • Explain how to safely charge a battery.
      • Discuss how to perform a battery drain test.
  • Objectives
    • The student should be able to:
      • Describe how to perform a battery load test.
      • Explain how to conduct a conductance test.
      • Discuss how to test batteries for open-circuit voltage and specific gravity.
  • BATTERY SERVICE SAFETY CONSIDERATIONS
  • Battery Service Safety Considerations
    • Hazards
      • Batteries contain acid and release explosive gases during normal charging and discharging cycles.
  • Battery Service Safety Considerations
    • Safety Procedures
      • Always adhere to these safety procedures:
        • When working on electrical component, disconnect negative battery cable.
  • Battery Service Safety Considerations
    • Safety Procedures
      • Always adhere to these safety procedures:
        • Wear eye protection (goggles preferred) when working around any battery.
        • Wear protective clothing to avoid skin contact with battery acid.
  • Battery Service Safety Considerations
    • Safety Procedures
      • Always adhere to these safety procedures:
        • Always adhere to safety precautions in service procedures for equipment used for battery service and testing.
  • Battery Service Safety Considerations
    • Safety Procedures
      • Always adhere to these safety procedures:
        • Never smoke or use open flame around any battery.
  • SYMPTOMS OF A WEAK OR DEFECTIVE BATTERY
  • Symptoms of a Weak or Defective Battery
    • Warning Signs
      • Uses water in one or more cells.
      • Excessive corrosion on battery cables or connections.
  • Figure 51-1 A visual inspection on this battery shows the electrolyte level was below the plates in all cells.
  • Figure 51-2 Corrosion on a battery cable could be an indication that the battery itself is either being overcharged or is sulfated, creating a lot of gassing of the electrolyte.
  • Symptoms of a Weak or Defective Battery
    • Warning Signs
      • Slower than normal engine cranking.
  • BATTERY MAINTENANCE
  • Battery Maintenance
    • Need for Maintenance
      • Most new-style batteries are maintenance-free.
      • They use lead-calcium instead of lead-antimony grid plate construction.
  • Battery Maintenance
    • Need for Maintenance
      • They release less gas.
      • There is less consumption of water.
  • Battery Maintenance
    • Need for Maintenance
      • Less gassing causes less corrosion on battery terminals.
      • If electrolyte level can be checked and it is low, add only distilled water.
  • Battery Maintenance
    • Need for Maintenance
      • Keep battery case clean.
      • Check battery cables and hold-down fasteners.
  • Battery Maintenance
    • Battery and Terminal Cleaning
      • Many battery-related faults are due to poor electrical connections at battery.
  • Battery Maintenance
    • Battery and Terminal Cleaning
      • Check for the following conditions.
        • Loose or corroded connections at battery terminals.
  • Battery Maintenance
    • Battery and Terminal Cleaning
      • Check for the following conditions.
        • Loose or corroded connections at ground connector on engine block.
  • Battery Maintenance
    • Battery and Terminal Cleaning
      • Check for the following conditions.
        • Wiring that has been modified to add auxiliary power.
  • Battery Maintenance
    • Battery and Terminal Cleaning
      • For corroded connections, use 1 tablespoon of baking soda in 1 quart (liter) of water and brush onto batter and housing to neutralize acid.
      • Mechanically clean connections and wash area with water.
  • Figure 51-3 Besides baking soda and water, a sugar-free diet soft drink can also be used to neutralize the battery acid.
  • Battery Maintenance
    • Battery Hold-Down
      • Ensure battery is secured with hold-down bracket to prevent vibration.
  • BATTERY VOLTAGE TEST
  • Battery Voltage Test
    • State of Charge
      • Test battery voltage with voltmeter.
      • Voltage does not necessarily indicate whether battery can perform satisfactorily.
  • Figure 51-4 (a) A voltage reading of 12.28 volts indicates that the battery is not fully charged and should be charged before testing.
  • Figure 51-4 (b) A battery that measures 12.6 volts or higher after the surface charge has been removed is 100% charged.
  • Battery Voltage Test
    • State of Charge
      • It does give more information than visual inspection.
      • Test is commonly called open circuit battery voltage test.
  • Battery Voltage Test
    • State of Charge
      • If battery has just been charged or vehicle recently driven, remove surface charge.
        • Surface charge is a charge of higher-than-normal voltage that is on just the surface of the battery plates.
  • Battery Voltage Test
    • State of Charge
      • If battery has just been charged or vehicle recently driven, remove surface charge.
        • Surface charge does not accurately represent battery ’s state of charge.
  • Battery Voltage Test
    • State of Charge
      • To remove surface charge, turn headlights on high for one minute.
        • Turn off headlights and wait two minutes.
  • Battery Voltage Test
    • State of Charge
      • With engine and accessories off and doors shut, connect voltmeter to battery posts.
        • Connect red positive lead to positive post.
  • Battery Voltage Test
    • State of Charge
      • With engine and accessories off and doors shut, connect voltmeter to battery posts.
        • Connect black negative lead to negative post.
  • Battery Voltage Test
    • State of Charge
      • With engine and accessories off and doors shut, connect voltmeter to battery posts.
        • NOTE: If the meter reads negative (–), the battery has been reverse charged (reversed polarity) and should be replaced, or the meter has been connected incorrectly.
  • Battery Voltage Test
    • State of Charge
      • Read voltmeter and compare with state of charge.
        • Voltages shown are for battery at or near room temperature (70°F to 80°F, or 21°C to 27°C).
  • Chart 51-1 The estimated state of charge of a 12 volt battery after the surface charge has been removed.
  • HYDROMETER TESTING
  • Hydrometer Testing
    • If battery has removable filler caps, specific gravity of electrolyte can be checked.
    • Hydrometer is a tester that measures specific gravity.
    • Test can be performed on most maintenance-free batteries because their filler caps are removable.
  • Figure 51-5 When testing a battery using a hydrometer, the reading must be corrected if the temperature is above or below 80°F (27°C).
  • Hydrometer Testing
    • Specific gravity test indicates state of battery charge.
    • Test can indicate defective battery if specific gravity varies more than 0.050 among cells.
  • Chart 51-2 Measuring the specific gravity can detect a defective battery. A battery should be at least 75% charged before being load tested.
  • BATTERY LOAD TESTING
  • Battery Load Testing
    • Terminology
      • Load test is one way to determine condition of any battery.
      • Most automotive starting and charging testers create electrical load.
  • Battery Load Testing
    • Terminology
      • Amount of load is determined by original CCA rating of battery.
      • Capacity is measured in cold-cranking amperes—the number of amperes a battery can supply at 0°F (–18°C) for 30 seconds.
  • Battery Load Testing
    • Test Procedure
      • STEP 1: Determine the CCA rating of battery.
        • Proper electrical load to test battery is one-half CCA rating or three times ampere-hour rating with minimum 150 ampere load.
  • Figure 51-6 This battery has cold-cranking amperes (CCA) of 550 A, cranking amperes (CA) of 680 A, and load test amperes of 270 A listed on the top label. Not all batteries have this complete information.
  • Battery Load Testing
    • Test Procedure
      • STEP 2: Connect load tester to battery and follow instructions for tester.
      • STEP 3: Apply load for a full fifteen seconds.
        • Observe voltmeter during load testing and check voltage after 15 seconds and while battery is still under load.
  • Battery Load Testing
    • Test Procedure
      • STEP 3: Apply load for a full fifteen seconds.
        • A good battery should have above 9.6 V.
  • Battery Load Testing
    • Test Procedure
      • STEP 4: Repeat the test.
        • Many battery manufacturers recommend two tests, one to remove surface charge and second for truer indication of battery condition.
  • Battery Load Testing
    • Test Procedure
      • STEP 4: Repeat the test.
        • Wait 30 seconds between tests.
  • Figure 51-7 An alternator regulator battery starter tester (ARBST) automatically loads the battery with a fixed load for 15 sec. to remove the surface charge, then removes the load for 30 sec. to allow the battery to recover, and then reapplies the load for another 15 sec. The results of the test are then displayed.
  • Battery Load Testing
    • If battery fails load test, recharge battery and retest.
    • If battery fails second test, replace battery.
    ? ?
  • ELECTRONIC CONDUCTANCE TESTING
  • Electronic Conductance Testing
    • Terminology
      • GM, Chrysler, and Ford specify electronic conductance tester to test batteries in vehicles under warranty.
  • Electronic Conductance Testing
    • Terminology
      • Conductance is measure of how well battery can create current.
      • Tester sends small signal through battery and measures part of AC response.
  • Electronic Conductance Testing
    • Terminology
      • Conductance testers can determine the following information.
        • CCA
        • State of charge
  • Electronic Conductance Testing
    • Terminology
      • Conductance testers can determine the following information.
        • Voltage
        • Defect such as shorts and opens
  • Electronic Conductance Testing
    • Terminology
      • Conductance tester will not accurately determine state of charge or CCA rating.
  • Electronic Conductance Testing
    • Terminology
      • Conductance tester can be used on discharged batter.
      • This type tester should only be used to test batteries that have been in service.
  • Figure 51-10 A conductance tester is very easy to use and has proved to accurately determine battery condition if the connections are properly made. Follow the instructions on the display exactly for best results.
  • Electronic Conductance Testing
    • Test Procedure
      • STEP 1: Connect unit to positive and negative terminals of battery:
        • If testing a side post battery, always use lead adapters and never use steel bolts; these can give incorrect reading.
  • Electronic Conductance Testing
    • Test Procedure
      • STEP 1: Connect unit to positive and negative terminals of battery:
        • NOTE: Test results can be incorrectly reported on the display if proper, clean connections to the battery are not made. Also be sure that all accessories and the ignition switch are in the off position.
  • Electronic Conductance Testing
    • Test Procedure
      • STEP 2: Enter CCA rating (if known) and push arrow keys.
      • STEP 3: Tester determines and displays one of the following:
        • Good battery.
  • Electronic Conductance Testing
    • Test Procedure
      • STEP 3: Tester determines and displays one of the following:
        • Charge and retest.
        • Replace the battery.
  • Electronic Conductance Testing
    • Test Procedure
      • STEP 3: Tester determines and displays one of the following:
        • Bad cell – replace.
      • Some conductance testers can check charging and cranking circuits.
  • BATTERY CHARGING
  • Battery Charging
    • Charging Procedure
      • It is best to slow charge any battery to prevent overheating damage to battery.
  • Battery Charging
    • Charging Procedure
      • Follow these steps.
        • STEP 1: Determine charge rate.
          • Charge rate based on current state of charge and charging rate.
  • Chart 51-3 Battery charging guideline showing the charging times that vary according to state of charge, temperature, and charging rate. It may take eight hours or more to charge a fully discharged battery. *Correct for temperature **If colder, it ’ll take longer
  • Battery Charging
    • Charging Procedure
        • STEP 2: Connect battery charger to battery.
          • Charger should not be plugged in when connecting to battery.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Initial charge rate should be about 35 A for 30 minutes.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Fast charging can increase temperature and warp plates.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Fast charging also increases gassing.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Battery temperature should not exceed 125°F.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Fast charge 15 A maximum.
  • Battery Charging
    • Charging Procedure
        • STEP 3: Set charging rate.
          • Slow charge 5 A maximum.
  • Figure 51-11 A typical industrial battery charger. Be sure that the ignition switch is in the off position before connecting any battery charger. Connect the cables of the charger to the battery before plugging the charger into the outlet. This helps prevent a voltage spike and spark that could occur if the charger happened to be accidentally left on. Always follow the battery charger manufacturer ’s instructions.
  • Battery Charging
    • Charging ATM Batteries
      • Charging an absorbed glass mat (AGM) battery requires different charger.
      • AGM battery can be charged with high current, up to 75% of ampere-hour rating due to lower internal resistance.
  • Battery Charging
    • Charging ATM Batteries
      • Charging voltage must be kept at or below 14.4 volts.
      • Most conventional battery chargers use charging voltage of 16 volts or higher.
  • Chart 51-4 A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • Chart 51-4 (continued) A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • Chart 51-4 (continued) A summary chart showing where the 12 volt and high-voltage batteries and shut-off switch/plugs are located. Only the auxiliary 12 volt batteries can be serviced or charged.
  • BATTERY CHARGE TIME
  • Battery Charge Time
    • Time can be estimated using reserve capacity rating in minutes divided by charging rate.
      • Hours needed to charge battery = Reserve capacity ÷ Charge current.
  • JUMP STARTING
  • Jump Starting
    • To jump start another vehicle with dead battery, connect good-quality copper jump cables or a jump box to batteries.
  • Figure 51-13 A typical battery jump box used to jump start vehicles. These hand-portable units have almost made jumper cables obsolete.
  • Jump Starting
    • Spark may be created when jumper cables complete the jumping circuit.
    • Spark could cause explosion of gases around battery.
  • Jump Starting
    • Many newer vehicles have special ground and/or positive power connections away from battery.
    • Check owner ’s manual or service information for location.
    ?
  • BATTERY ELECTRICAL DRAIN TEST
  • Battery Electrical Drain Test
    • Terminology
      • Battery electrical drain test determines if a component or circuit is causing a drain on battery.
      • Test also called ignition off draw (IOD) or parasitic load test.
  • Battery Electrical Drain Test
    • Terminology
      • Many electronic components draw a continuous, slight amount of current from battery with ignition off.
        • Electronically tuned radios for station memory and clock circuits.
  • Battery Electrical Drain Test
    • Terminology
      • Many electronic components draw a continuous, slight amount of current from battery with ignition off.
        • Computers and controllers through diode leakage.
  • Battery Electrical Drain Test
    • Terminology
      • Many electronic components draw a continuous, slight amount of current from battery with ignition off.
        • Alternator through diode leakage.
  • Battery Electrical Drain Test
    • Terminology
      • These components may cause voltmeter to read full battery voltage.
      • Voltmeters should not be used for battery drain testing.
  • Battery Electrical Drain Test
    • Terminology
      • Battery drain test should be performed under these conditions:
        • When battery is being charged or replaced.
          • Battery drain might have caused charging or replacing.
  • Battery Electrical Drain Test
    • Terminology
      • Battery drain test should be performed under these conditions:
        • When battery is suspected of being drained.
  • Battery Electrical Drain Test
    • Terminology
      • Battery drain test should be performed under these conditions:
        • When battery is suspected of being drained.
          • Inductive DC ammeter.
            • Fastest and easiest method to measure battery electrical drain.
  • Figure 51-16 This mini clamp-on digital multimeter is being used to measure the amount of battery electrical drain that is present. In this case, a reading of 20 mA (displayed on the meter as 00.02 A) is within the normal range of 20 to 30 mA. Be sure to clamp around all of the positive battery cable or all of the negative battery cable, whichever is easiest to get the clamp around.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • DMM set to read milliamperes.
      • STEP 1: Turn off lights, accessories, ignition.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • STEP 2: Check all vehicle doors to be certain courtesy lights are off.
      • STEP 3: Disconnect negative battery cable; install parasitic load tool.
  • Figure 51-17 After connecting the shut-off tool, start the engine and operate all accessories. Stop the engine and turn off everything. Connect the ammeter across the shut-off switch in parallel. Wait 20 minutes. This time allows all electronic circuits to "time out" or shut down. Open the switch—all current now will flow through the ammeter. A reading greater than specified (usually greater than 50 mA, or 0.05 A) indicates a problem that should be corrected.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • STEP 4: Start engine and drive vehicle 10 minutes.
        • Turn on all lights and accessories.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • STEP 5: Turn engine and accessories off.
      • STEP 6: Connect ammeter across parasitic load tool switch.
        • Wait 20 minutes for all computers and circuits to shut down.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • STEP 7: Open switch on load tool and read battery electrical drain on meter display.
  • Battery Electrical Drain Test
    • Procedure for Battery Electrical Drain Test
      • NOTE: Using a voltmeter or test light to measure battery drain is not recommended by most vehicle manufacturers. The high internal resistance of the voltmeter results in an irrelevant reading that does not provide the technician with adequate information about a problem.
  • Battery Electrical Drain Test
    • Specifications
      • Normal = 20 to 30 mA (0.02 to 0.03 A).
      • Maximum allowable = 50 mA (0.05 A).
  • Battery Electrical Drain Test
    • Reset All Memory Functions
      • Reset clock, "auto up" windows, antitheft radio.
  • Figure 51-18 The battery was replaced in this Acura and the radio displayed "code" when the replacement battery was installed. Thankfully, the owner had the five-digit code required to unlock the radio.
  • Battery Electrical Drain Test
    • Battery Drain and Reserve Capacity
      • Some self-discharge of battery is normal.
      • GM estimates normal self-discharge at about 13 mA (0.013 A).
  • Battery Electrical Drain Test
    • Battery Drain and Reserve Capacity
      • Some manufacturers specify maximum allowable parasitic draw or battery drain based on reserve capacity of battery.
      • Calculation is reserve capacity of battery divided by 4.
  • Battery Electrical Drain Test
    • Finding the Source of the Drain
      • Check and temporarily disconnect the following components.
        • Underhood light.
  • Battery Electrical Drain Test
    • Finding the Source of the Drain
      • Check and temporarily disconnect the following components.
        • Glove compartment light.
        • Trunk light.
  • Battery Electrical Drain Test
    • Finding the Source of the Drain
      • If drain remains in excess of 50 mA (0.05A), disconnect one fuse at a time from fuse box until excessive drain drops to normal.
  • Battery Electrical Drain Test
    • Finding the Source of the Drain
      • NOTE: Do not reinsert fuses after they have been removed as this action can cause modules to "wake up," leading to an inconclusive test.
  • Battery Electrical Drain Test
    • Finding the Source of the Drain
      • If drain stops after disconnecting a fuse, the drain is located in that circuit.
      • Disconnect the power-side wire connectors from each component in that circuit until test light goes out.
  • Battery Electrical Drain Test
    • What to Do If a Battery Drain Still Exists
      • If all fuses have been disconnected and the drain continues, the source must be between battery and fuse box.
  • Battery Electrical Drain Test
    • What to Do If a Battery Drain Still Exists
      • Two common sources of drain under the hood include:
        • Alternator.
          • Disconnect alternator wires and retest battery.
  • Battery Electrical Drain Test
    • What to Do If a Battery Drain Still Exists
      • Two common sources of drain under the hood include:
        • Starter solenoid or wiring near its components.
    ?
  • BATTERY SYMPTOM GUIDE
  • The following list will assist technicians in troubleshooting batteries.
  • TECH TIP
    • Dynamic versus Open Circuit Voltage
      • Open circuit voltage is the voltage (usually of a battery) that exists without a load being applied. Dynamic voltage is the voltage of the power source (battery) with the circuit in operation. A vehicle battery, for example, may indicate that it has 12.6 volts or more, but that voltage will drop when the battery is put under a load such as cranking the engine.
    BACK TO PRESENTATION
    • If the battery voltage drops too much, the starter motor will rotate more slowly and the engine may not start.
    • If the dynamic voltage is lower than specified, the battery may be weak or defective or the circuit may be defective.
  • FREQUENTLY ASKED QUESTION
    • What Is the Three-Minute Charge Test?
      • A three-minute charge test is used to check if a battery is sulfated, and is performed as follows:
    ? BACK TO PRESENTATION
      • Connect a battery charger and a voltmeter to the battery terminals.
      • Charge the battery at a rate of 40 amperes for three minutes.
      • At the end of three minutes, read the voltmeter.
    • Results: If the voltage is above 15.5 volts, replace the battery. If the voltage is below 15.5 volts, the battery is not sulfated and should be charged and retested.
    • This is not a valid test of many maintenance-free batteries, such as the Delphi Freedom. Due to the high internal resistance, a discharged Delphi Freedom battery may not start to accept a charge for several hours. Always use another alternative battery test before discarding a battery based on the results of the three-minute charge test.
  • FREQUENTLY ASKED QUESTION
    • How Should You Test a Vehicle Equipped with Two Batteries?
      • Many vehicles equipped with a diesel engine use two batteries. These batteries are usually electrically connected in parallel to provide additional current (amperes) at the same voltage.
    ? BACK TO PRESENTATION Some heavy-duty trucks and buses connect two batteries in series to provide about the same current as one battery, but with twice the voltage. To successfully test the batteries, they should be disconnected and tested separately. If just one battery is found to be defective, most experts recommend that both be replaced to help prevent future problems. Because the two batteries are electrically connected, a fault in one battery can cause the good battery to discharge into the defective battery, thereby affecting both even if just one battery is at fault.
      • Figure 51-8 Most light-duty vehicles equipped with two batteries are connected in parallel as shown. Two 500 A, 12 volt batteries are capable of supplying 1,000 A at 12 volts, which is needed to start many diesel engines.
      • Figure 51-9 Many heavy-duty trucks and buses use two 12 volt batteries connected in series to provide 24 volts.
  • SAFETY TIP
    • Never Charge or Jump Start a Frozen Battery
      • A discharged battery can freeze because the electrolyte becomes mostly water. Never attempt to charge or jump start a vehicle that has a frozen battery. When the battery freezes, it often bulges at the sides because water expands about 9% when it freezes, forming ice crystals that occupy more space than liquid water.
    BACK TO PRESENTATION
      • The crystals can trap bubbles of hydrogen and oxygen that are created during the chemical processes in a battery. When attempting to charge or jump start the frozen battery, these pockets of gases can explode. Because the electrolyte expands, the freezing action usually destroys the plates and can loosen the active material from the grids. It is rare for a frozen battery to be restored to useful service.
  • TECH TIP
    • Charge Batteries at 1% of Their CCA Rating
      • Many batteries are damaged due to being overcharged. To help prevent damage such as warped plates and excessive release of sulfur smell gases, charge batteries at a rate equal to 1% of the battery ’s CCA rating.
    BACK TO PRESENTATION
    • For example, a battery with a 700 CCA rating should be charged at 7 amperes (700 × 0.01 = 7 amperes). No harm will occur to the battery at this charge rate even though it may take longer to achieve a full charge. This means that a battery may require eight or more hours to become fully charged depending on the battery capacity and state of charge (SOC).
  • TECH TIP
    • Always Use Adapters on Side Post Batteries
      • Side post batteries require that an adapter be used when charging the battery, if it is removed from the vehicle. Do not use steel bolts.
    BACK TO PRESENTATION
    • If a bolt is threaded into the terminal, only the parts of the threads that contact the battery terminal will be conducting all of the charging current. An adapter or a bolt with a nut attached is needed to achieve full contact with the battery terminals.
      • Figure 51-12 Adapters should be used on side terminal batteries whenever charging.
  • FREQUENTLY ASKED QUESTION
    • Should Batteries Be Kept Off of Concrete Floors?
      • All batteries should be stored in a cool, dry place when not in use. Many technicians have been warned not to store or place a battery on concrete.
    ? BACK TO PRESENTATION
    • According to battery experts, it is the temperature difference between the top and the bottom of the battery that causes a difference in the voltage potential between the top (warmer section) and the bottom (colder section). It is this difference in temperature that causes self-discharge to occur.
    • In fact, submarines cycle seawater around their batteries to keep all sections of the battery at the same temperature to help prevent self-discharge.
    • Therefore, always store or place batteries up off the floor and in a location where the entire battery can be kept at the same temperature, avoiding extreme heat and freezing temperatures. Concrete cannot drain the battery directly because the case of the battery is a very good electrical insulator.
  • TECH TIP
    • Look at the Battery Date Code
      • All major battery manufacturers stamp codes on the battery case that give the date of manufacture and other information. Most battery manufacturers use a number to indicate the year of manufacture and a letter to indicate the month of manufacture, except the letter I, because it can be confused with the number 1.
    • For example:
      • A = January
      • B = February
      • C = March
      • D = April
      • E = May
      • F = June
      • G = July
      • H = August
      • J = September
      • K = October
      • L = November
      • M = December
    • The shipping date from the manufacturing plant is usually indicated by a sticker on the end of the battery. Almost every battery manufacturer uses just one letter and one number to indicate the month and year.
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      • Figure 51-15 The code on the Delphi battery indicates that it was built in 2005 (5), in February (B), on the eleventh day (11), during third shift (C), and in the Canadian plant (Z).
  • REAL WORLD FIX
    • The Chevrolet Battery Story
      • A 2005 Chevrolet Impala was being diagnosed for a dead battery. Testing for a battery drain (parasitic draw) showed 2.25 A, which was clearly over the acceptable value of 0.050 or less.
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    • At the suggestion of the shop foreman, the technician used a Tech 2 scan tool to check if all of the computers and modules went to sleep after the ignition was turned off. The scan tool display indicated that the instrument panel (IP) showed that it remained awake after all of the others had gone into sleep mode.
    • The IP cluster was unplugged and the vehicle was tested for an electrical drain again. This time, it was only 32 mA (0.032 A), well within the normal range. Replacing the IP cluster solved the excessive battery drain.
  • TECH TIP
    • It Could Happen to You!
      • The owner of a Toyota replaced the battery. After doing so, the owner noted that the "airbag" amber warning lamp was lit and the radio was locked out. The owner had purchased the vehicle used and did not know the four-digit security code needed to unlock the radio.
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    • Determined to fix the problem, the owner tried three four-digit numbers, hoping that one of them would work. However, after three tries, the radio became permanently disabled.
    • Frustrated, the owner went to a dealer. It cost over $300 to fix the problem. A special tool was required to easily reset the airbag lamp. The radio had to be removed and sent out of state to an authorized radio service center and then reinstalled into the vehicle.
    • Therefore, before disconnecting the battery, check to be certain that the owner has the security code for a security-type radio. A "memory saver" may be needed to keep the radio powered up when the battery is being disconnected.
      • Figure 51-19 (a) Memory saver. The part numbers represent components from Radio Shack.
      • Figure 51-19 (b) A schematic drawing of the same memory saver. Some experts recommend using a 12 volt lantern battery instead of a small 9 volt battery to help ensure that there will be enough voltage in the event that a door is opened while the vehicle battery is disconnected. Interior lights could quickly drain a small 9 volt battery.
  • FREQUENTLY ASKED QUESTION
    • Where Is the Battery?
      • Many vehicle manufacturers today place the battery under the backseat, under the front fender, or in the trunk.
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    • Often, the battery is not visible even if it is located under the hood. When testing or jump starting a vehicle, look for a battery access point.
      • Figure 51-20 Many newer vehicles have batteries that are sometimes difficult to find. Some are located under plastic panels under the hood, under the front fender, or even under the rear seat as shown here.
  • TECH TIP
    • Check the Battery Condition First
      • A discharged or defective battery has lower voltage potential than a good battery that is at least 75% charged. This lower battery voltage cannot properly power the starter motor. A weak battery could also prevent the charging voltage from reaching the voltage regulator cutoff point.
    • This lower voltage could be interpreted as indicating a defective alternator and/or voltage regulator. If the vehicle continues to operate with low system voltage, the stator winding in the alternator can be overheated, causing alternator failure.
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