“When most motorists think of dead batteries that cause starting failure, they think of severe winter weather, but summer heat is the real culprit,” said Nathan Perrine, executive director, Car Care Council. “Many battery problems start long before the temperatures drop. Heat, more than cold, shortens battery life.”
Sooner or later all batteries have to be replaced. Excessive heat and overcharging are the two main reasons for shortened battery life. Heat causes battery fluid to evaporate, thus damaging the internal structure of the battery. A malfunctioning component in the charging system, usually the voltage regulator, allows too high a charging rate, leading to slow death for a battery.