1. Chapter 31
Battery Systems

2. Testing the Battery’s State of Charge
31-1
Check and adjust the fluid level. Charge the battery if distilled water is added. Test the specific gravity of each of the cells by using a hydrometer designed for battery testing. Draw some of the electrolyte into the tester and read the scale.

3. Testing the Battery’s State of Charge
31-1
To test the specific gravity with a refractometer, place a drop or two of electrolyte on the specimen window and lower the cover plate. Look into the eyepiece with the refractometer under a bright light. Read the scale for battery acid. The point where the dark area meets the light area is the reading.

4. Testing the Battery’s State of Charge
31-1
To conduct an open circuit voltage test, select the volts DC position on your DVOM and attach the probes to the battery terminals (red to positive, black to negative). Compare the reading to Table 31-1.

5. 31-2 Load Testing a Battery
With the tester controls off and the load control turned to the off position, connect the tester leads to the battery. Place the inductive amps clamp around either the black or the red tester cables in the correct orientation.

6. 31-2 Load Testing a Battery
Verify that the temperature of the battery is within the testing parameters. Use an infrared temperature gun to determine the temperature by measuring the temperature of the side of the battery. If you are using an automatic load tester, enter the battery’s CCA and select “test” or “start.” If you are using a manual load tester, calculate the test load, which is usually half of the CCA.

7. 31-2 Load Testing a Battery
Maintain this load for 15 seconds while watching the voltmeter. Read the voltmeter and immediately turn the control knob off. At room temperature, the voltage should be 9.6 volts or higher at the end of the 15-second draw. If the battery is colder than room temperature, look up the compensated minimum voltage. Determine any necessary action.

8. Identifying Electronic Modules, Security Systems, Radios and Other Accessories that Require Reintialization or Code Entry Following Battery Disconnect
31-3
In the appropriate service information or owner’s manual, find the section that lists the information on the electronic modules, security systems, radios, and other accessories that require reinitialization or code entry. For example, the immobilizer, radio, engine, and transmission each have their own section.

9. Identifying Electronic Modules, Security Systems, Radios and Other Accessories that Require Reintialization or Code Entry Following Battery Disconnect
31-3
From the service information, list the systems and modules that may require initialization.
Keys / 4-3
Smart key / 4-6
Remote keyless entry / 4-12
Theft-alarm system / 4-15
Door locks / 4-19

10. Maintaining or Restoring Electronic Memory Functions
31-4
Identify which modules, if any, require reinitialization or code entry when the battery is disconnected following Skill Drill 31-3.
Keys / 4-3
Smart key / 4-6
Remote keyless entry / 4-12
Theft-alarm system / 4-15
Door locks / 4-19

11. Maintaining or Restoring Electronic Memory Functions
31-4
Identify the correct procedure and any needed tools, and verify that initialization codes are available.

12. Maintaining or Restoring Electronic Memory Functions
31-4
If maintaining memory function, install a memory minder prior to the vehicle battery being disconnected. If reinitializing the electronic systems is required, use the correct codes supplied by the manufacturer.

13. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Remove the cable clamp from the negative terminal first. Then remove the positive terminal. Bend the cables back out of the way so that they cannot fall back and touch the battery terminals accidentally.

14. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Remove the battery hold-downs or other hardware securing the battery.

15. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Keeping it upright, remove the battery from its tray and place it on a clean work surface. Inspect the battery for damage.

16. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Measure the voltage on the top of the battery with a DVOM. Place the black lead on the negative post and move the red lead across the top of the battery until you find the highest reading.

17. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Carefully clean the battery case and the battery tray.

18. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Clean the battery posts with a battery terminal tool. Clean the cable terminals with the same battery terminal tool. Examine the battery cables for fraying or corrosion.

19. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Reinstall the cleaned and serviced battery. Replace the hold-downs and make sure the battery is securely held in positions. If installing a new battery, ensure that it meets the original manufacturer’s specifications.

20. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Reconnect the positive battery terminal and tighten it in place. Once the positive terminal is finished, reconnect the negative terminal and tighten it.

21. Inspecting, Cleaning, Filling, and Replacing the Battery and Cables
31-5
Coat the terminal connections with anti-corrosive paste or spray to keep oxygen from the terminal connections. Test that you have a good electrical connection by starting the vehicle.

22. Charging a Battery
31-6
Verify whether the battery needs to be disconnected during charging and, if so, whether the adaptive memory needs to be maintained. Inspect the battery casing and ensure that the battery has not been frozen. Verify that the charger is unplugged and off. Connect the red lead to the positive terminal and the black lead to the negative terminal.

23. Charging a Battery
31-6
Turn the charger on to a slow, automatic charge.

24. Charging a Battery
31-6
Once the battery is charged, turn the charger off. Allow the battery to stand for at least 5 minutes before testing the battery. Using a capacitance tester, load tester, refractometer, or hydrometer, test the charged state of the battery.

25. Jump-Starting a Vehicle
31-7
Position the vehicle with the charged battery close to the vehicle with the discharged battery, but not touching. Connect the red or orange lead to the positive terminal of the discharged battery.

26. Jump-Starting a Vehicle
31-7
Connect the other end of this red or orange lead to the positive terminal of the charged battery.

27. Jump-Starting a Vehicle
31-7
Connect the black lead to the negative terminal of the charged battery.

28. Jump-Starting a Vehicle
31-7
Connect the other end of the black lead to a paint-free ground on the engine block of the vehicle with the discharged battery.

29. Jump-Starting a Vehicle
31-7
Start the vehicle with the discharged battery. Turn the headlights on to prevent a possible voltage spike damaging the electronic equipment. Disconnect the jumper leads in the reverse order that you connected them. If the charging system is working correctly and the battery is in good condition, the battery will be recharged while the engine is running.

30. Measuring Parasitic Draw—Standard Test
31-8
Research the parasitic draw specifications in the service information. Connect the low-current clamp around the negative battery cable and measure the parasitic draw. Compare the parasitic draw to specifications.

31. Measuring Parasitic Draw—Standard Test
31-8
Disconnect the circuit fuses one at a time to determine which circuit has the excessive parasitic current draw. Determine any necessary actions.

32. Measuring Parasitic Draw—Chesney Parasitic Load Test
31-9
Set the DVOM to read ohms (lowest scale if available). Connect the leads together and read the meter screen. This is the meter’s delta reading.

33. Measuring Parasitic Draw—Chesney Parasitic Load Test
31-9
Place the black meter lead on the negative battery post and the red lead on the alternator case.

34. Measuring Parasitic Draw—Chesney Parasitic Load Test
31-9
Read the meter and compare the reading to the Chesney parasitic load ratio graph. If there is excessive parasitic load, pull fuses one at a time to identify the faulty circuit.