1. Batteries and Fuses Topics covered in this presentation:
Battery Operating Principles
Battery Construction

2. Objectives: By the end of this lesson you should be able to:
Identify why we need a battery in a car
Describe the basic construction of a battery
Identify Energy Convertions
State the nominal value of a cell
Work out the nominal value of a battery

3. The Battery Electrical systems require electrical power to function.
Alternator provides electrical power when engine is running.
Battery provides electrical power when engine is stationary.
A large amount of battery power is required to start an engine.
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4. Question 1
When is the most electrical power required from an automobile battery?
A) When the headlights are turned on
B) When the engine is started
Correct Answer = B
C) When the horn is used
D) When the automobile is stationary

5. Fundamental battery cell
Batteries - Active Materials
Positive plate
Negative plate
Electrolyte
Separator
Load
Fundamental battery cell
Container
Battery plates contain active materials that react with the electrolyte.
Positive plate active material is lead peroxide, negative plate active material is porous lead.
Electrolyte is made from sulphuric acid and distilled water.
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6. Question 2 What does the positive plate of a car battery contain?
A) Lead
B) Lead sulphate
Correct Answer = C
C) Lead peroxide
D) Lead nitrate

7. Batteries - Cell Construction
Positive plates
Negative plates
Grid
Lead straps / connectors
Plates
Plates contain grids that hold the active material and provide an electrical path.
Plate Groups
Alternate positive and negative plates are grouped together, and connected by straps.
Separators
Separators
Insulate the plates from each other, but allow electrolyte to flow freely.
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8. Batteries - Cells
An element contains plate groups and separators, and is commonly known as a cell.
Each cell produces about 2V, so 6 cells are required for a 12V battery.
Cells are connected in series by lead straps.
Straps across end cells are part of the terminals.
Battery terminals
Lead straps
Cell (x6)
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9. Question 3
What voltage, in V, approximately, does each cell of a battery produce?
Enter your answer and press SEND.
Correct Answer =

10. Batteries - Discharging and Charging
(described using conventional current flow techniques)
Discharging
Discharging occurs when current flows out of a battery.
Current is produced when a load is placed across battery terminals.
Battery converts stored chemical energy into electrical energy.
Charging
Charging occurs when current flows into battery.
Requires an external voltage that is higher than the battery voltage.
On a vehicle, the charging voltage is provided by an alternator.
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11. Question 4
Which of the following correctly describes the main energy change occurring when a battery is discharging?
A) electrical to chemical
B) potential to kinetic
Correct Answer = C
C) chemical to electrical
D) chemical to heat and light

12. Batteries - Chemical Action
Electrolyte chemically reacts with lead plates.
Discharging
Electrolyte hydrogen combines with positive plate oxygen to form water.
Electrolyte sulphate combines with lead on plates to form lead sulphate.
Charging
Current flow reverses chemical action.
Sulphate is forced back into electrolyte and combines with hydrogen, while oxygen returns to the positive plate to form lead peroxide.
Process continues while voltage is applied, until all lead sulphate is converted.
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13. Question 5
As an automobile battery discharges the electrolyte becomes more dilute. Is this true or false?
Answer True or False.
Correct Answer = T

14. Batteries - Ratings Labels on battery case indicate battery ‘rating’.
Capacity - Ampere-Hour Rating
Amount of current a battery can supply over a given period of time (20 27°C (80°F).
Capacity - Cold Start Rating
Current battery can provide over a set period of time -18°C (0°F).
Capacity - Reserve Capacity Rating
Time battery can supply 27°C (80°F) before the individual cell voltages drop below 1.7V.
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15. Question 6
Which of the following units measures the capacity of a battery?
A) Ampere
B) Volt
Correct Answer = D
C) Watt
D) Ampere-hour

16. Batteries - Case
Case is made of polypropylene (plastic) or a hard rubber compound.
Dividers help separate cells.
Ribs at bottom of each cell collect excess material from plates.
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17. Batteries - Case Cover is sealed to the top of the case.
Openings above each cell for screw-in plugs or snap-in caps, in low-maintenance batteries.
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18. Batteries - Terminals and Cables
Battery Terminals
Battery has terminals for cable connections.
Positive terminal is usually bigger.
Common types are:
Battery Cables
Cables connect to battery using cable ends.
Battery cables carry large currents and are very thick.
Cables should be kept short for ease of routing.
Lug or L terminal
Side terminal
Post terminal
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19. Question 7 Why are battery cables very thick?
A) Because they carry large currents
B) Because vibration causes thin cables to fracture
Correct Answer = A
C) Because they must not bend easily
D) Because they have to be attached to large connectors

20. Batteries - Maintenance Free Batteries
Sealed for life, no need to top-up with electrolyte.
Built-in relative density indicator.
Green = fully charged.
Black = requires charging.
Yellow = electrolyte low.
Reservoir to collect evaporated water.
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21. Objectives: By the end of this lesson you should be able to:
Identify why we need a battery in a car
Describe the basic construction of a battery
Identify the 3 main chemical parts
State the nominal value of a cell
Work out the nominal value of a battery

22. LJ
34:91 Batteries
First 4 chapters