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

Question 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
(i)	Overcharged battery
(ii)	Low state of charge
(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.