Safety Prevent Battery Explosions Keep sparks, lighted matches, and open flame away from the top of battery. Battery gas can explode. Never check battery charge by placing a metal object across the posts. Use a volt-meter or hydrometer. TS204 –UN–23AUG88 Do not charge a frozen battery; it may explode. Warm battery to 16 ° C (60 ° F). Battery Explosions DX,SPARKS –19–03MAR93–1/1 05-13 021604 PN=28