Question 42 OSE01 - Chief Engineer - OSV

The Correct Answer is A **Why Option A is Correct:** When lead-acid battery electrolyte is frozen, it indicates that the battery is severely discharged, as fully charged batteries have a much lower freezing point (due to higher sulfuric acid concentration). Attempting to use or charge a frozen battery is dangerous and can cause permanent damage. If current is drawn or applied, the frozen water may block the ion movement necessary for chemical reactions, potentially leading to overheating, case rupture, or plate warping. The safest and recommended procedure is to first allow the battery to thaw naturally and completely. Once thawed, the low state of charge that caused the freezing must be corrected by recharging the battery before attempting to use it for cranking. **Why the Other Options are Incorrect:** * **B) The engine should be started by means of jumper cables connected to another battery without any particular concern regarding the electrolyte being frozen.** This is incorrect and dangerous. While using jumper cables bypasses the requirement for the frozen battery to provide power, the frozen battery is still connected to the system. Applying a high load or connecting it to a running charging system while it is frozen can cause internal pressure buildup or physical damage to the battery case and plates, posing a safety risk. * **C) The battery electrolyte should be thawed by means of a battery charger, and then the battery should be recharged as necessary before attempting to start the engine.** This is incorrect. Applying a charge (which generates heat) to a severely discharged and frozen battery is dangerous. The internal resistance in the frozen sections can cause localized overheating, and the ice may prevent the relief of gasses, leading to an explosion risk or severe damage to the battery cells. Thawing must be done passively or externally, not by using the charger itself. * **D) The battery electrolyte should be allowed to thaw, and then the battery electrolyte should be diluted with distilled water as necessary before attempting to start the engine.** This is incorrect. The freezing occurred because the battery was discharged (low concentration of sulfuric acid, high concentration of water). Diluting the electrolyte further with distilled water would lower the specific gravity even more, making the battery weaker and increasing the risk of refreezing. If the specific gravity needs adjustment, it should only be done after the battery has been fully charged.