Why Car Batteries Die in Arizona Heat, and How to Make Yours Last

Heat, not cold, is what wears a car battery out. High temperatures speed up the chemical reactions inside it and break it down faster, and under-hood temperatures can top 200°F in summer. AAA says a battery in hot southern climates typically lasts about three years, compared with five or more in cooler northern states. In the Phoenix area, plan on replacing yours every three to four years. Source →

The summer heat did the damage; the cold morning just exposed it. Heat weakens the battery over the hot months, and when temperatures drop, the engine oil thickens and takes more power to crank while the weakened battery delivers less. That’s why so many batteries fail in the fall, right after a hot summer. Source →

A slow, labored crank when you start the car is the most common sign, along with a clicking sound, the battery or charging warning light, dim headlights at idle, or a battery that needs a jump after sitting a day or two. A swollen or cracked battery case, or heavy white or blue corrosion on the terminals, also means it’s on its way out. If yours is three or more years old, have it tested before it strands you.

Set the multimeter to DC volts and touch the red lead to the positive terminal and the black lead to the negative, with the engine off and the car sitting for a few hours. About 12.6 volts means fully charged; about 12.4 is roughly 75%, 12.2 is about half, and under 12.0 means it’s discharged. With the engine running, you should see about 13.5 to 14.5 volts, which means the alternator is charging. Our battery diagnostic walks you through every step, including a cranking test.

Usually, yes. Most auto parts stores will test your battery and charging system free, often right in the parking lot, and many repair shops check it during an oil change. Also look for the date sticker on the battery, which shows the month and year it was made or installed; in Arizona, a battery more than three years old is worth testing every year.

Modern cars slowly drain the battery even when they’re off, and a battery that goes completely dead is often damaged for good. If the car will sit for more than a few weeks, especially through an Arizona summer, connect a smart battery maintainer (a trickle charger that switches itself off), or have someone start and drive it for 20 minutes every couple of weeks. Disconnecting the negative cable also works, though it may reset the radio and clock. Park in a garage or the shade when you can.

Match the group size, the type and the minimum cold cranking amps (CCA) your owner’s manual calls for; a much higher rating isn’t needed and doesn’t help in the heat. If your car has engine start-stop or came with an AGM battery, replace it with an AGM battery. Some newer cars also need the new battery registered with a scan tool so the charging system treats it correctly. Buy a fresh battery (check the date code, ideally under six months old) with at least a three-year free replacement warranty. Source →

Wear safety glasses and gloves. To clean corrosion, disconnect the negative (black) cable first, scrub the terminals with a mix of baking soda and water and a wire brush, rinse, dry, and reconnect positive first and negative last. To jump-start, connect red to the dead battery’s positive, red to the good battery’s positive, black to the good battery’s negative, and the last black clamp to bare metal on the dead car’s engine, away from the battery, because batteries give off hydrogen gas that a spark can ignite. Never jump a battery that’s frozen, cracked or swollen.