In my experience, ethylene glycol with water is the most widely utilized coolant in battery cooling systems. What is the commonly used coolant in battery cooling? This mixture helps keep the battery system from freezing or boiling and has good heat transmission qualities. Because of its effectiveness in preserving ideal battery temperatures which are essential for optimizing performance and longevity it is highly recommended. However, to determine which coolant is best for your battery system, always refer to the manufacturer's instructions.