Here’s hot news about your car battery that may seem surprising: It’s not so much the cold that gets it down as it is high heat. Heat causes battery fluid to evaporate, thus damaging the internal structure of the battery. That’s why it’s a good idea to check your battery as the seasons change from hotter to cooler or if you’ve been driving in a hot part of the country.
Another reason for shortened battery life is overcharging. That is, a malfunctioning component in the charging system, usually the voltage regulator, can allow too high a charging rate, leading to slow death for a battery.
In addition, colder temperatures can increase the thickness of the engine oil, making the engine harder to turn over, causing the battery to have to work more. These factors lead to harder starting.
What You Can Do
• 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. Add distilled water when necessary.
• Always replace a battery with one that’s rated at least as high as the one originally specified.
• Have the battery checked if you notice headlights and interior lights dim, accessories that fail to operate, or the “check engine” or battery light illuminated.
• 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.