The freezing point of electrolyte depends on the electrolyte's specific gravity. Freezing may ruin a battery. Protect the battery against freezing by maintaining a charged condition. The battery will not freeze if the green dot shows in the built-in hydrometer. The battery will not freeze unless the temperature drops below -32°C (-25°F). A fully charged battery will not freeze unless the temperature drops below -54°C (-65°F).