"Heat kills car batteries," according to John Banta, a Consumer Reports project leader and part of the team that tests batteries for the magazine. "Many times in cold climates, your battery fails to start your car on a below-freezing day. The reason this happens is that the heat of the past summers has weakened your battery. When you use it in the cold, the starter requires more electrical current to turn over the cold engine with its thickened oil." Leaving your car parked or stored for long periods of time can also lead to a dead battery that you will need to recharge before heading out for a drive.
The car battery itself may be the cause if it has corroded cable terminals, bad wiring, damaged cells or plates inside or if it is leaking electrolyte. This article refers primarily to conventional vehicles with conventional 12-volt batteries; more electrified vehicles and those higher-voltage electrical systems will vary. The charging system warning light should show for a few seconds when you start the car, but if the battery light shows while you're driving the vehicle, that light signals a problem. Among other signs that the alternator or other parts of the charging system aren't working are dim headlights or the clock losing time.
Here's what causes this: A blown fuse for the system, A wheel-speed sensor that is damaged or covered by road grime, A broken wire between the sensors and the ABS controller, An ABS controller that has stopped working. A pump and valve that apply the right amount of brake fluid pressure to each wheel to prevent locking can also trigger an ABS sensor warning light when those items go bad. If the red warning light for the regular brakes comes on, that typically means your vehicle is losing brake fluid or the brakes are so worn that you don't have normal stopping power. Either of those situations warrants immediate attention and possible repair work.
You rely on your car's battery to start your car every time you turn the key. Whether you are driving to work or just hitting the road for a day of fun, you need to know that your battery is up to the job. Unfortunately, batteries don't last forever, and even new car batteries will eventually need to be replaced. How long should the battery in your vehicle last? The answer isn't always straightforward, and in many cases, it isn't as long as drivers think it should be.