ASE A6 Certification: Battery Diagnosis and Service

2. OBJECTIVES After studying Chapter 17, the reader 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.

3. BATTERY SERVICE SAFETY CONSIDERATIONS • Batteries contain acid and release explosive gases (hydrogen and oxygen) during normal charging and discharging cycles. • To help prevent physical injury or damage to the vehicle, always adhere to the following safety procedures. 1. When working on any electrical component on a vehicle, disconnect the negative battery cable from the battery. When the negative cable is disconnected, all electrical circuits in the vehicle will be open, which will prevent accidental electrical contact between an electrical component and ground.

4. BATTERY SERVICE SAFETY CONSIDERATIONS 2. Wear eye protection when working around any battery. 3. Wear protective clothing to avoid skin contact with battery acid. 4. Always adhere to all safety precautions as stated in the service procedures for the equipment used for battery service and testing. 5. Never smoke or use an open flame around any battery.

5. WHAT ARE SYMPTOMS OF A WEAK OR DEFECTIVE BATTERY? • There are several warning signs to indicate that a battery is near the end of its useful life, including: • Uses water in one or more cells. • This indicates that the plates are sulfated and that during the charging process, the water in the electrolyte is being turned into separate hydrogen and oxygen gases. FIGURE 17-1 A visual inspection of this battery showed that the electrolyte level was below the plates in all cells.

6. WHAT ARE SYMPTOMS OF A WEAK OR DEFECTIVE BATTERY? • Excessive corrosion on battery cables or connections.Corrosion is more likely to occur if the battery is sulfated, creating hot spots on the plates. • When the battery is being charged, the acid fumes are forced out of the vent holes and get onto the battery cables, connections, and even on the battery tray underneath the battery. FIGURE 17-2 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.

7. WHAT ARE SYMPTOMS OF AWEAK OR DEFECTIVE BATTERY? • Slower than normal engine cranking. • When the capacity of the battery is reduced due to damage or age, it is less likely to be able to supply the necessary current for starting the engine, especially during cold weather.

8. BATTERY MAINTENANCE • Most new-style batteries are of a maintenance-free design that uses lead-calcium instead of lead-antimony plate grid construction. • Battery maintenance includes making certain that the battery case is clean and checking and adding clean water, if necessary. FIGURE 17-3 Many maintenance-free batteries can be opened to check the electrolyte level without damaging the battery. Notice the surface dirt, which could cause the battery to self-discharge.

9. BATTERY MAINTENANCE • Do not overfill a battery, because normal bubbling (gassing) of the electrolyte will cause the electrolyte to escape and start corrosion on the battery terminals, hold-down brackets, and battery tray.

10. BATTERY MAINTENANCE • Another method is to fill the battery until the water becomes “puckered,” indicating that the electrolyte level is even with the bottom of the filler tube. FIGURE 17-4 The electrolyte level is correct if the liquid looks curved when observed from above. This curve is called the meniscus and is formed when the liquid clings to the surface of the fill tube in each cell (if equipped).

11. BATTERY VOLTAGE TEST • Testing the battery voltage with a voltmeter is a simple method for determining the state of charge of any battery. FIGURE 17-5 (a) A battery voltage of 12.28 volts is definitely not fully charged and should be charged before testing. (b) A battery that measures 12.60 volts or higher after the surface charge has been removed is 100% charged.

12. BATTERY LOAD TESTING • Many battery manufacturers recommend performing the load test twice, using the first load period to remove the surface charge on the battery and the second test to provide a truer indication of the condition of the battery.

13. BATTERY LOAD TESTING FIGURE 17-7 A typical battery load tester hookup. FIGURE 17-6 A Sun Electric VAT-40 (volt amp tester—Model 40) connected to a battery for load testing. The technician turns the load knob until the ammeter registers an amperage reading equal to one-half of the battery’s CCA rating. The load is maintained for 15 seconds, and the voltage of the battery should be higher than 9.6 volts at the end of the time period with the load still applied.

14. BATTERY LOAD TESTING FIGURE 17-8 This battery has cold-cranking amperes (CCA) of 550 A, cranking amperes (CA) of 680 A, and load test amperes of 270 A listed right on the top label. Not all batteries have all of this information. FIGURE 17-9 An alternator regulator battery starter tester (ARBST) automatically loads the battery with a fixed load for 15 seconds to remove the surface charge, then removes the load for 30 seconds to allow the battery to recover, and then reapplies the load for another 15 seconds. The results of the test are then displayed.

15. BATTERY LOAD TESTING FIGURE 17-10 The minimum capacity test voltage varies with battery temperature.

16. 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. FIGURE 17-11 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 amperes at 12 volts, which is needed to start many diesel engines.

17. HOW SHOULD YOU TEST A VEHICLE EQUIPPED WITH TWO BATTERIES? • 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. FIGURE 17-12 Many heavy-duty trucks and buses use two 12 volt batteries connected in series to provide 24 volts.

18. ELECTRONIC CONDUCTANCE TESTING • Conductance is a measure of how well a battery can create current. • The unit can determine the CCA, state of charge, (soc) and voltage of the battery and detect all defects, such as shorts and opens. FIGURE 17-13 The display on an electronic battery tester showing that the battery tested was good. It compares the rated CCA rating with the measured CCA capacity to help determine if the battery is good.

19. ELECTRONIC CONDUCTANCE TESTING • Connect the unit to the positive and negative terminals of the battery and, after entering the CCA rating (if known), push the arrow keys. • The tester determines one of the following: • Good battery. The battery can return to service. • Charge and retest. Fully recharge the battery and return it to service. • Replace the battery. The battery is not serviceable and should be replaced. • Bad cell—replace. The battery is not serviceable and should be replaced

20. BATTERY CHARGING • If the state of charge of a battery is low, it must be recharged. • It is best to slow-charge any battery to prevent possible overheating damage to the battery. FIGURE 17-14 Battery charging guide. Battery charging times vary according to state of charge, temperature, and charging rate.

21. BATTERY CHARGING • Remember, it may take eight hours or more to charge a fully discharged battery. FIGURE 17-15 A typical industrial battery charger. Be sure that the ignition switch is in the off position before connecting any battery charges. Connect the cables of the charger to the battery before plugging the charger into the outlet. This helps prevent a voltage spike that could occur if the charger happened to be accidentally left on. Always follow the battery charger manufacturer’s instruction.

22. CHARGING AGM BATTERIES • Absorbed glass mat batteries are usually used as auxiliary in hybrid electric vehicles when the battery is located inside the vehicle.

23. BATTERY CHARGE TIME • The time needed to charge a completely discharged battery can be estimated by using the reserve capacity rating of the battery in minutes divided by the charging rate. • Hours needed to charge the battery = Reserve capacity ÷ Charge current

24. ALWAYS USE ADAPTERS ON SIDEPOST BATTERIES • Side-post batteries require that an adapter be used when charging the battery, if it is removed from the vehicle. • An adapter or a bolt with a nut attached is needed to achieve full contact with the battery terminals. FIGURE 17-16 Adapters should be used on side-terminal batteries when charging.

25. JUMP STARTING • To jump start another vehicle with a dead battery, connect good-quality copper jumper cables FIGURE 17-17 Jumper cable usage guide. Notice that the last connection should be the engine block of the disabled vehicle to help prevent the spark that normally occurs from igniting the gases from the battery.

26. JUMP STARTING • Even if using a battery jump box, the last connection made should always be on the engine block or an engine bracket as far from the battery as possible. FIGURE 17-18 A typical battery jump box used to jump start vehicles. These hand-portable units have almost made jumper cables obsolete.

27. BATTERY DATE CODES • All major battery manufacturers stamp codes on the battery case that give the date of manufacture and other information. • A = January • B = February • C = March • D = April • E = May • F = June • G = July • H = August • J = September • K = October • L = November • M = December

28. BATTERY DATE CODES • 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. FIGURE 17-19 The code on the Delphi battery indicates that it was built in 2005 (5),in February (B), on the 11th (11),during third shift (C), and in the Canadian plant (Z).

29. BATTERY ELECTRICAL DRAIN TEST • The battery electrical drain test determines if some component or circuit in a vehicle is causing a drain on the battery when everything is off. • This test is also called the ignition off draw (IOD) or parasitic load test.

30. BATTERY ELECTRICAL DRAIN TEST • This test should be performed when one of the following conditions exists. • When a battery is being charged or replaced (a battery drain could have been the cause for charging or replacing the battery) • When the battery is suspected of being drained

31. IT COULD HAPPEN TO YOU! • 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 17-20 (a) Memory saver. The part numbers represent components from Radio Shack. (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.

32. PROCEDURE FOR BATTERY ELECTRICAL DRAIN TEST • The fastest and easiest method to measure battery electrical drain is to connect an inductive DC ammeter that is capable of measuring low current (10 mA). FIGURE 17-21 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.

33. PROCEDURE FOR BATTERY ELECTRICAL DRAIN TEST • Following is the procedure for performing the battery electrical drain test using a DMM set to read DC amperes. • Make certain that all lights, accessories, and ignition are off. • Check all vehicle doors to be certain that the interior courtesy (dome) lights are off. • Disconnect the negative (-) battery cable and install a parasitic load tool. FIGURE 17-22 Parasitic load tool. After connecting the shut-off tool, start the engine and operate all accessories. Stop the engine and turn everything off. Connect the ammeter across the shut-off switch in parallel. Wait 20 minutes. This time allows all electronic circuits to “timeout” or shutdown. Open the switch— all current now will flow through the ammeter. A reading greater than specified (usually greater than 50 milliamperes [0.05 ampere]) indicates a problem that should be corrected.

34. PROCEDURE FOR BATTERY ELECTRICAL DRAIN TEST 4. Start the engine and drive the vehicle about 10 minutes, being sure to turn on all the lights and accessories including the radio. 5. Turn the engine and all accessories off including the underhood light. 6. Connect an ammeter across the parasitic load tool switch and wait 10 minutes for all computers and circuits to shut down. 7. Open the switch on the load tool and read the battery electrical drain on the meter display.

35. PROCEDURE FOR BATTERY ELECTRICAL DRAIN TEST • Be sure to reset the clock and antitheft radio if equipped. FIGURE 17-23 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.

36. BATTERY DRAIN AND RESERVE CAPACITY • It is normal for a battery to self-discharge even if there is not an electrical load such as computer memory to drain the battery. • The calculation used is the reserve capacity of the battery divided by 4; this equals the maximum allowable battery drain.

37. FINDING THE SOURCE OF THE DRAIN • If there is a drain, check and temporarily disconnect the following components. • Light under the hood (Some lights under the hood are hot all the time and light by means of a mercury switch when the hood is opened.) • Glove compartment light • Trunk light

38. WHAT TO DO IF A BATTERY DRAIN STILL EXISTS • If all the fuses have been disconnected and the drain still exists, the source of the drain has to be between the battery and the fuse box. • The generator. Disconnect the generator wires and retest. If the ammeter now reads a normal drain, the problem is a defective diode(s) in the generator. • The starter solenoid (relay) or wiring near its components. These are also a common source of battery drain, due to high current flows and heat, which can damage the wire or insulation.

39. HIDDEN BATTERIES • Many vehicle manufacturers today place the battery under the backseat, under the front fender, or in the trunk. FIGURE 17-24 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. The battery in this Lincoln LS was located in the trunk next to the spare tire. The jump start instructions indicate that the spare tire hold-down bolt is to be used as the ground connection if jump starting is necessary.

40. BATTERY SYMPTOM GUIDE • The following list will assist technicians in troubleshooting batteries.

41. BATTERY LOAD TESTStep-by-Step

42. BATTERY LOAD TESTStep-by-Step cont

43. BATTERY LOAD TESTStep-by-Step cont

44. SUMMARY • All batteries should be securely attached to the vehicle with hold-down brackets to prevent vibration damage. • Batteries can be tested with a voltmeter to determine the state of charge. A battery load test loads the battery to one-half of its CCA rating. A good battery should be able to maintain higher than 9.6 volts for the entire 15-second test period. • A battery drain test should be performed if the battery runs down.

45. REVIEW QUESTIONS • Describe the results of a voltmeter test of a battery and its state of charge. • List the steps for performing a battery load test. • Explain how to perform a battery drain test.

46. CHAPTER QUIZ • Technician A says that distilled or clean drinking water should be added to a battery when the electrolyte level is low. Technician B says that fresh electrolyte (solution of acid and water) should be added. Which technician is correct? • Technician A only • Technician B only • Both Technicians A and B • Neither Technician A nor B

47. CHAPTER QUIZ 2. All batteries should be in a secure bracket that is bolted to the vehicle to prevent physical damage to the battery. • True • False

48. CHAPTER QUIZ 3. A battery date code sticker indicates D6. What does this mean? • The date it was shipped from the factory was December 2006. • The date it was shipped from the factory was April 2006. • The battery expires in December 2002. • It was built the second day of the week (Tuesday).

49. CHAPTER QUIZ 4. Many vehicle manufacturers recommend that a special electrical connector be installed between the battery and the battery cable when testing for _____. • Battery drain (parasitic drain) • Specific gravity • Battery voltage • Battery charge rate

50. CHAPTER QUIZ 5. When load testing a battery, which battery rating is usually used to determine how much load to apply to the battery? • CA • RC • MCA • CCA