Car batteries typically last 3–5 years, and a few signs tell you it’s time: slow or labored cranking, headlights that dim at idle, a battery warning light, or a visibly swollen case. If you’re unsure, most auto-parts stores will load-test a battery for free to confirm whether it’s actually weak.
Match the replacement
Buy a battery that matches your vehicle’s group size (the physical dimensions and terminal layout), its cold-cranking amps (CCA) rating, and its type (don’t downgrade an AGM vehicle to flooded). All of these are listed in the owner’s manual or printed on the old battery.
Safe terminal order
The disconnect/reconnect sequence prevents accidental short circuits:
- Removing: disconnect the negative (−) terminal first, then the positive (+).
- Installing: connect the positive (+) first, then the negative (−).
Disconnecting negative first means that if your wrench touches the car body while loosening it, nothing happens — the body is already at negative potential. Clean any corrosion off the terminals, make sure the battery is strapped down so it can’t vibrate, and expect to reset the clock and radio presets afterward.
Frequently asked questions
How long do car batteries last? Usually 3–5 years.
Which terminal first? Negative first when removing; positive first when installing.
How do I pick the right battery? Match group size, CCA, and type to your vehicle.