Auto Electrical Works Paper 2, May/June 2015

Question 1

  1. Define a battery.
  2. A 12V lead acid battery is being charged. After some time, there was an explosion and the electrolyte spilled on the auto electrical technician.
  3. State;

    (i) Two possible causes of the explosion; (ii) The immediate treatment that should be given to the auto electrical technician.
  4. The electrolyte level in a battery in use exposes parts of the plates.
    (i) What is the effect of this on the battery if it is left unattended to for a month? (ii) State the precaution to be taken to avoid this situation.



           The expected answers were;

  1. Definition of a battery
  2. (i)A battery is a device that converts chemical energy into electrical energy (ii) The assembly of two or more cells together
  3. (i)   Causes of battery treatment
  4. (a)Overcharging (b) Spark from the battery terminal connection (c)Closed vent plugs during charge (d)If the battery electrolyte freezes

    (ii)   First aid treatment

    (a)Wash it thoroughly with clean water/baking soda/alkali (and apply petroleum jelly) (b)Give first aid treatment

  5. (i)  Effect of low level of electrolyte
  • It leads to permanent damage to the battery
  • Sulphation
  •  (ii)  Precautions against low level of electrolyte

  • Always maintain the electrolyte level above the minimum
  • Fill lines on the battery and at or below the minimum line
  •  Regular inspection of the battery
  • The candidates were required to define a battery, state two possible causes of explosion during charging, how to administer treatment if someone is affected by the electrolyte spillage. They were to state the effect of not maintaining a battery with its plates exposed and state precautions to be taken when a battery’s plates are exposed.
    The candidates’ performance was reported to be below average in this question.