2. OBJECTIVES
After studying Chapter 16, the reader should be able to:
Prepare for ASE Electrical/Electronic Systems (A6) certification test content area (Battery Diagnosis and Service).
Describe how a battery works.
List battery ratings.
Describe deep cycling.
Discuss how charge indicators work.

3. PURPOSE OF A BATTERY
Everything electrical in a vehicle is supplied current from the battery.
The battery is one of the most important parts of a vehicle because it is the heart or foundation of the electrical system.

4. BATTERY CONSTRUCTION
Most automotive battery cases (container or covers) are constructed of polypropylene, a thin (approximately 0.08 in. [0.02 mm]thick), strong, and lightweight plastic.
Built into the bottom of many batteries are ribs that support the lead-alloy plates and provide a space for sediment to settle, called the Sediment Chamber.

5. BATTERY CONSTRUCTION
FIGURE 16-1 A typical polypropylene plastic battery case.

6. GRIDS
Each positive and negative plate in a battery is constructed on a framework, or grid, made primarily of lead.
FIGURE 16-2 The grid provides support for the plate active material.

7. GRIDS Maintenance-Free versus Standard Battery Grids
Maintenance-free batteries use calcium instead of antimony, because 0.2% calcium has the same strength as 6% antimony.
Low-maintenance batteries use a low percentage of antimony(about 2% to 3%), or use antimony only in the positive plates and calcium for the negative plates.

8. GRIDS Radial-Grid Design
Some batteries use a grid design with only vertical and horizontal strips.
The current must move over and up along the grid strips to reach point A.
FIGURE 16-3 Current created at point B must travel to point A to be able to reach the battery terminals.

9. GRIDS Radial-Grid Design
With a radial grid design (radial means branching out from a common center), the current generated near point B can travel directly to point A.
FIGURE 16-4 Radial design battery grids permit lower resistance for current flow by joining the branches of the grids.

10. GRIDS Positive Plates
The positive plates have lead dioxide (peroxide) placed onto the grid framework.
This active material can react with the sulfuric acid of the battery and is dark brown in color.

11. GRIDS Negative Plates
The negative plates are pasted with a pure porous lead,called sponge lead, and are gray in color.

12. GRIDS Separators
The positive and the negative plates must be installed alternately next to each other without touching.
Many batteries use envelope-type separators that encase the entire plate and help prevent any material that may shed from the plates from causing a short circuit between plates at the bottom of the battery.

13. GRIDS Cells
Cells are constructed of positive and negative plates with insulating separators between each plate.
Most batteries use one more negative plate than positive plate in each cell.
FIGURE 16-5 Two groups are interlaced to form a battery element.

14. GRIDS Partitions
Each cell is separated from the other cells by partitions,which are made of the same material as that used for the outside case of the battery.
FIGURE 16-6 A cutaway battery showing the connection of the cells to each other through the partition.

15. GRIDS Electrolyte
The electrolyte used in automotive batteries is a solution (liquid combination) of 36% sulfuric acid and 64% water.
This electrolyte is used for both lead-antimony and lead-calcium(maintenance-free) batteries.

16. HOW A BATTERY WORKS
A fully charged lead-acid battery has a positive plate of lead dioxide (peroxide) and a negative plate of lead surrounded by a sulfuric acid solution (electrolyte).

17. HOW A BATTERY WORKS During Discharging
The positive plate lead dioxide (PbO2) combines with the SO4, forming PbSO4 from the electrolyte and releases its O2 into the electrolyte, forming H2O.
FIGURE 16-7 Chemical reaction for a lead-acid battery that is fully charged being discharged by the attached electrical load.

18. HOW A BATTERY WORKS The Fully Discharged State
When the battery is fully discharged, both the positive and the negative plates are PbSO4 (lead sulfate) and the electrolyte has become water (H2O).

19. HOW A BATTERY WORKS During Charging
During charging, the sulfate (acid) leaves both the positive and the negative plates and returns to the electrolyte, where it becomes normal-strength sulfuric acid solution.
FIGURE 16-8 Chemical reaction for a lead-acid battery that is fully discharged being charged by the attached generator.

20. SPECIFIC GRAVITY
The amount of sulfate in the electrolyte is determined by the electrolyte’s specific gravity, which is the ratio of the weight of a given volume of a liquid to the weight of an equal volume of water.
FIGURE 16-9 As the battery becomes discharged, the specific gravity of the battery acid decreases.

21. SPECIFIC GRAVITY Charge Indicators
Some batteries are equipped with a built-in state-of-charge indicator.
When the ball floats, it appears in the hydrometer’s sight glass, changing its color.
FIGURE Typical battery charge indicator. If the specific gravity is low (battery discharged), the ball drops away from the reflective prism. When the battery is charged enough, the ball floats and reflects the color of the ball (usually green) back up through the sight glass, and the sight glass is dark.

22. SPECIFIC GRAVITY VERSUS STATE OF CHARGE AND BATTERY
VOLTAGE
Values of specific gravity, state of charge, and battery voltage at 80°F (27°C) are given in the following list.

23. VALVE REGULATED LEAD-ACID BATTERIES
There are two basic types of valve regulated lead-acid (VRLA), also called sealed valve-regulated (SVR) or sealed lead-acid (SLA), batteries.

24. VALVE REGULATED LEAD-ACID BATTERIES Absorbed glass mat (AGM).
The acid used in an absorbed glass mat (AGM) battery is totally absorbed into the separator, making the battery leak-proof and spill proof.
FIGURE An absorbed glass mat battery is totally sealed and is more vibration resistant than conventional lead-acid batteries.

25. VALVE REGULATED LEAD-ACID BATTERIES Gelled electrolyte batteries.
In a gelled electrolyte battery, silica is added to the electrolyte, which turns the electrolyte into a substance similar to gelatin.
This type of battery is also called a gel battery.

26. CAUSES AND TYPES OF BATTERY FAILURE
Most batteries have a useful service life of three to seven years; however, proper care can help increase the life of a battery, but abuse can shorten it.
FIGURE Battery that was accidentally left over the weekend on a battery charger that was set for a high charge rate. Note how the plates warped and the top blew off.

27. BATTERY HOLD-DOWNS
All batteries must be attached securely to the vehicle to prevent battery damage.
Battery hold-down clamps or brackets help reduce vibration, which can greatly reduce the capacity and life of any battery.

28. BATTERY RATINGS
Batteries are rated according to the amount of current they can produce under specific conditions.
Cold-Cranking Amperes
Cranking Amperes
Marine Cranking Amperes
Reserve Capacity
Ampere Hour

29. DEEP CYCLING
Deep cycling is almost fully discharging a battery and then completely recharging it.
Charging is hard on batteries because the internal heat generated can cause plate warpage, so these specially designed batteries use thicker plate grids that resist warpage.

30. BATTERY COUNCIL INTERNATIONAL GROUP SIZES
The Battery Council International (BCI) organization has established battery group size designations.

31. BATTERY COUNCIL INTERNATIONAL GROUP SIZES

32. BATTERY COUNCIL INTERNATIONAL GROUP SIZES

33. WHAT CAN CAUSE A BATTERY TO EXPLODE?
Batteries discharge hydrogen gas and oxygen when being charged. If there happens to be a flame or spark, the hydrogen will burn.
FIGURE (a) A small spark inside the battery was the most likely cause of this battery explosion. Parts of the battery were thrown 30 ft (10 m); luckily, no one was around the vehicle at the time. (b) Because battery acid was spilled and sprayed around the battery, the entire area was rinsed with water after unplugging the
battery charger.

34. SUMMARY
Maintenance-free batteries use lead-calcium grids instead of lead-antimony grids to reduce gassing.
When a battery is being discharged, the acid (SO4) is leaving the electrolyte and being deposited on the plates. When the battery is being charged, the acid (SO4) is forced off the plates and back into the electrolyte.
Batteries are rated according to CCA and reserve capacity.

35. REVIEW QUESTIONS Explain why discharged batteries can freeze.
Identify the three most commonly used battery-rating methods.
Explain why a battery can explode if exposed to an open flame or spark.

36. CHAPTER QUIZ
When a battery becomes completely discharged, both positive and negative plates become _____ and the electrolyte becomes _____.
H2SO4 /Pb
PbSO4 /H2O
PbO2 /H2SO4
PbSO4 /H2SO4

37. CHAPTER QUIZ
When a battery becomes completely discharged, both positive and negative plates become _____ and the electrolyte becomes _____.
H2SO4 /Pb
PbSO4 /H2O
PbO2 /H2SO4
PbSO4 /H2SO4

38. 2. A fully charged 12 volt battery should indicate _____.
CHAPTER QUIZ
2. A fully charged 12 volt battery should indicate _____.
12.6 volts or higher
A specific gravity of or higher
12 volts
Both a and b

39. 2. A fully charged 12 volt battery should indicate _____.
CHAPTER QUIZ
2. A fully charged 12 volt battery should indicate _____.
12.6 volts or higher
A specific gravity of or higher
12 volts
Both a and b

40. 3. Deep cycling means _____.
CHAPTER QUIZ
3. Deep cycling means _____.
Overcharging the battery
Overfilling or underfilling the battery with water
The battery is fully discharged and then recharged
The battery is overfilled with acid (H2SO4)

41. 3. Deep cycling means _____.
CHAPTER QUIZ
3. Deep cycling means _____.
Overcharging the battery
Overfilling or underfilling the battery with water
The battery is fully discharged and then recharged
The battery is overfilled with acid (H2SO4)

42. 4. What makes a battery “low maintenance” or “maintenance free”?
CHAPTER QUIZ
4. What makes a battery “low maintenance” or “maintenance free”?
Alloy is used to construct the grids.
The plates are constructed of different metals.
The electrolyte is hydrochloric acid solution.
The battery plates are smaller, making more room for additional electrolytes.

43. 4. What makes a battery “low maintenance” or “maintenance free”?
CHAPTER QUIZ
4. What makes a battery “low maintenance” or “maintenance free”?
Alloy is used to construct the grids.
The plates are constructed of different metals.
The electrolyte is hydrochloric acid solution.
The battery plates are smaller, making more room for additional electrolytes.

44. 5. The positive battery plate is _____.
CHAPTER QUIZ
5. The positive battery plate is _____.
Lead dioxide
Brown in color
Sometimes called lead peroxide
All of the above

45. 5. The positive battery plate is _____.
CHAPTER QUIZ
5. The positive battery plate is _____.
Lead dioxide
Brown in color
Sometimes called lead peroxide
All of the above

46. 6. Which battery rating is tested at 0°F (-18°C)?
CHAPTER QUIZ
6. Which battery rating is tested at 0°F (-18°C)?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

47. 6. Which battery rating is tested at 0°F (-18°C)?
CHAPTER QUIZ
6. Which battery rating is tested at 0°F (-18°C)?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

48. 7. Which battery rating is expressed in minutes?
CHAPTER QUIZ
7. Which battery rating is expressed in minutes?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

49. 7. Which battery rating is expressed in minutes?
CHAPTER QUIZ
7. Which battery rating is expressed in minutes?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

50. 8. What battery rating is tested at 32°F (0°C)?
CHAPTER QUIZ
8. What battery rating is tested at 32°F (0°C)?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

51. 8. What battery rating is tested at 32°F (0°C)?
CHAPTER QUIZ
8. What battery rating is tested at 32°F (0°C)?
Cold-cranking amperes (CCA)
Cranking amperes (CA)
Reserve capacity
Battery voltage test

52. 9. What gases are released from a battery when it is being charged?
CHAPTER QUIZ
9. What gases are released from a battery when it is being charged?
Oxygen
Hydrogen
Nitrogen and oxygen
Hydrogen and oxygen

53. 9. What gases are released from a battery when it is being charged?
CHAPTER QUIZ
9. What gases are released from a battery when it is being charged?
Oxygen
Hydrogen
Nitrogen and oxygen
Hydrogen and oxygen

54. CHAPTER QUIZ
10. A charge indicator (eye) operates by showing green or red when the battery is charged and dark if the battery is discharged. This charge indicator detects _____.
Battery voltage
Specific gravity
Electrolyte water pH
Internal resistance of the cells

55. CHAPTER QUIZ
10. A charge indicator (eye) operates by showing green or red when the battery is charged and dark if the battery is discharged. This charge indicator detects _____.
Battery voltage
Specific gravity
Electrolyte water pH
Internal resistance of the cells

56. END