Auto Electrical Works Paper 2, WASSCE (SC), 2023

Question 1

 

  1. Question 1
    (a) Describe briefly in five steps the preparation of a lead-acid battery electrolyte.
    (b) List two types of test which a battery should pass in order to be considered worthy for use.
    (c) Table 1 contains underived battery state of charge.
    Complete the table by stating two symptoms and remedies for each of the listed conditions.
    Table 1


    S/N

    Condition

    Symptom

    Remedy

    (i)

    Overcharged battery

     

     

     

     

    (ii)

    Low state of charge

     

     

     

     

     

Observation

 

The expected responses were:

 

  •      Steps in the preparation of a lead acid battery electrolyte
  • Measure acid and distilled water in the ratio of 1 : 3.
  • Add acid to water gently in an acid-proof container
  • Stir gently with a glass rod/wood
  • Allow the mixture to cool
  • Measure the specific gravity of the electrolyte and ensure it reads 1.28
  •    Types of battery test
  • Voltage test: Voltmeter / Multimeter
  • Specific gravity test: Hydrometer
  • Load / Drain test: High rate discharge tester    
  • Digital multimeter testing
  • Conductance test
  • Load testing
  • Pico diagnostic battery test                                                     

 

  •                                                              Table 1

S/N

Condition

Symptoms

Remedy

(i)

Overcharged battery

  • High hydrometer reading
  • Frequent topping up
  • Burnt bulbs
  • Gassing
  • Swollen container
  • Blown electronics
  • Replace battery
  • Avoid overcharging
  • Reduce specific gravity of electrolyte
  • Check voltage regulator

(ii)

Low state of charge

  • Low hydrometer reading
  • Lack of power when starting
  • Poor/dim light from lamp
  • Change warning lamp on or blinking
  • Low ammeter reading
  • Replace battery
  • Recharge battery
  • Check alternator voltage regulator
  • Check and adjust alternator belt tension

 

As reported by the Chief Examiner, the performance of students in parts (a) and (b) of the question was average. However, in part (c), candidates’ performance was relatively below average.

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