Summer is the season for major car-battery problems. Heat, not cold, shortens battery life, says the Car Care Council.

Excessive heat and overcharging are the two main reasons for shortened battery life. Heat causes battery fluid to evaporate, this damaging the internal structure of the battery. A malfunctioning component in the charging system, usually the voltage regulator, allows too high a charging rate. That's slow death for a battery.

True, there are more road service calls in cold weather for dead batteries that cause starting failure. That's when a battery's output is diminished because of sluggish electro-chemical action that gives the battery its power. Also, colder temperatures increase thickness of the engine oil, making the engine harder to turn over. These factors lead to harder starting.

"An average of one out of four vehicles gets a new battery every year," said Rich White, executive director of the Car Care Council. "Sooner or later all batteries have to be replaced, but having to so prematurely can involve more than the cost of a road service call and a new battery, it can be inconvenient as well."

To get the most life out of a battery, White suggests the following:

• Be sure the electrical system is charging at the correct rate; overcharging can damage a battery as quickly as undercharging.

• If your battery is the type that needs to be topped off, check it regularly, especially in hot weather. Add distilled water when necessary.

• Always replace a battery with one that's rated at least as high as the one originally specified.

• Keep the top of the battery clean. Dirt becomes a conductor, which drains battery power. Further, as corrosion accumulates on battery terminals it becomes an insulator, inhibiting current flow.