Q: How Long Does a Car Battery Last?

Whether you drive a vehicle for work or roaming around town running errands, one constant reality is that we all depend on our car’s battery to start the vehicle on the roads we travel. However, one of the frequently asked questions we get is about how long a car battery lasts. The reality is that the lifespan of any car, truck, or SUV battery is dependent upon multiple variables including how often the vehicle is started, the weather or environment in which the vehicle operates, whether it’s charged by the owner, and the condition of other supporting components such as the alternator or ignition system.

If we were to assume that the battery in question operated under ideal conditions, including no excessive humidity or hot/cold temperatures, a perfect alternator, and an ignition system that doesn’t drain the battery, you can expect the battery in your vehicle to last anywhere from three to five years.

The batteries that are manufactured for cars, trucks, and SUVs today are rechargeable batteries, meaning they can be hooked up to a battery charger at home or an automotive shop. This process involves connecting a battery charger to the positive and negative terminals on the battery itself. With the battery charger set and turned on, electricity flows through the battery and stimulates the acid/water mixture and metallic core cells inside the battery.

Over a period of time, however, the battery components lose the ability to hold a charge, regardless of how often the owner attempts to manually charge the battery. When this happens, it is time to replace the battery.

Some of the variables that can reduce battery life, beyond the location and use of the vehicle, include:

• A malfunctioning alternator: The alternator creates an electrical charge that powers all vehicle electrical systems while the engine is running. This also allows the battery to recharge itself during operation.
• A malfunctioning ignition system: Sometimes an ignition relay switch will stick open, causing the battery to supply power to components like interior lights, dashboard lights, fuel pumps, or ignition components even if the key is not inserted.
• Leaving lights or auxiliary switches on.

The best way to extend the battery life is to stay on top of routine battery maintenance, which includes cleaning the battery terminals, charging the battery periodically, and making sure to service the vehicle by replacing alternator belts or having the alternator replaced as soon as an issue is discovered.