How long does a car battery last and what are the signs it's dying?

How long a car battery really lasts

A typical lead-acid car battery lasts about 3 to 5 years. Some go longer, especially in mild climates and on cars that get driven every day. Others give out in 2 or 3 years. The battery itself rarely tells you its age, so check the date code: most batteries have a sticker or stamp on the case showing the month and year they were made or installed.

Batteries wear out because the chemical reaction that stores power slowly degrades every time the battery charges and discharges. Heat speeds that process up. So does leaving the battery partly drained for long stretches.

What shortens battery life

These are the most common reasons a battery dies early:

• Summer heat. High temperatures under the hood speed up internal corrosion and fluid loss. Hot summers often do the damage that shows up in winter.
• Short trips. Starting the engine takes a big draw of power, and a 5-minute drive isn't long enough for the alternator to put it all back.
• Sitting unused. A car parked for weeks slowly drains its battery, and a battery left discharged loses capacity it doesn't get back.
• Accessories left on. Lights, dash cams, and chargers that stay powered with the engine off pull the battery down.
• Corroded or loose terminals. Poor connections keep the battery from charging and delivering power properly.
• A failing alternator. If the charging system isn't working, even a new battery won't stay charged.

Warning signs your battery is dying

A battery rarely dies with no warning. Watch for these signs:

• Slow cranking. The engine turns over sluggishly before it starts, especially on cold mornings.
• Clicking when you start. A rapid click with no crank usually means there isn't enough power to turn the starter.
• Dim lights. Headlights or interior lights look weak, or dim noticeably when you start the car.
• A battery warning light. This can mean a weak battery or a charging system problem, and both need attention.
• Electrical glitches. Power windows, the radio, or the infotainment screen act up or reset.
• Corrosion. White, green, or blue crust building up on the battery terminals.
• A swollen case. A battery that looks bloated or bulging has been damaged by heat or overcharging and should be replaced.
• A rotten-egg smell. A sulfur odor near the battery can mean it's leaking. Have it checked right away.
• Repeat jump starts. If you've needed a jump more than once, the battery is telling you it's done.

Why PA and NJ winters kill weak batteries

Cold doesn't usually ruin a healthy battery. It exposes a weak one. Low temperatures slow the chemical reaction inside the battery, so it delivers less power. At the same time, cold engine oil is thicker and the engine needs more power to turn over. A battery that was already worn down by age or summer heat can handle that in October and then fail on the first frosty morning in December.

That's why fall is the smartest time to test. A quick test now is a lot better than a dead car in a parking lot on a 20-degree morning. While you're getting ready for winter, it's also a good time for a tire rotation, and if you're thinking about a new vehicle, our guide to AWD vs. FWD vs. RWD in PA and NJ covers the drivetrain side of winter driving.

How to check your battery

The quick voltage check

If you have a multimeter, you can check resting voltage with the car off for at least a few hours. Here's what the reading means:

The load test

Voltage only tells part of the story. A battery can read 12.6 volts and still not have the strength to start the car. A load test, which most service centers can run in a few minutes, checks how the battery holds up while delivering the power needed to crank the engine. It's the most reliable way to know whether a battery will make it through the winter.

Replacing a car battery: what to know

A standard battery typically costs about $100 to $200, and an AGM battery often runs $200 to $350 before installation. A few things are worth knowing before you buy:

• Match the type. Many newer vehicles, especially those with engine start-stop, require an AGM battery. Putting a standard battery in its place can shorten its life and cause electrical issues.
• Match the specs. Group size and cold cranking amps (CCA) need to meet your manufacturer's requirements. Higher CCA helps in cold climates like ours.
• Some cars need registration. Many BMW, Mercedes-Benz, Audi, and other newer models need the new battery registered with a scan tool so the car charges it correctly.
• Check the alternator too. If a fairly new battery keeps dying, the charging system may be the real problem.

EV and hybrid owners: you have a 12-volt battery too

Most electric vehicles and hybrids still use a small 12-volt battery to run the computers, locks, and lights. It wears out on roughly the same timeline as a gas car's battery, and when it fails, the car may not power on even with a full high-voltage pack. The big battery that drives the car is a separate system built to last much longer, and most automakers warranty it for at least 8 years or 100,000 miles.

How to make your battery last longer

• Drive at least 20 to 30 minutes at a time on a regular basis so the alternator can fully recharge the battery.
• Use a battery maintainer if your car will sit for more than a couple of weeks.
• Keep the terminals clean and tight.
• Park in a garage when you can, to protect the battery from both summer heat and winter cold.
• Turn off lights and unplug accessories before you shut the car off.
• Have the battery tested each fall once it's 3 years old.

Keeping up with routine maintenance like oil changes gives a technician the chance to spot battery and charging problems early. If a warning light does come on, our check engine light guide explains what to do next.

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Car battery FAQ