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How To Know If A Car Battery Is Dead

Is your car battery about to fail? Has it already died? It's a common problem. In this guide, we'll tell you all about it and show you how to spot a problematic car battery.

What Are The Signs Of A Dead Battery In A Car?

There are a few signs that you have a dead or dying car battery, including:

The Ignition is Unresponsive

If your car doesn't respond when you turn the key, it likely means that the starter motor can't draw any power from the battery.

The Starter Motor Cranks but the Engine Doesn't Start

If the starter motor cranks slowly but the engine refuses to start, it means you either have a faulty starter or a dead car battery. If it's cranking normally, it could be the battery, fuel, or spark plug.

The Engine Starts and Then Dies

When the engine starts but dies shortly afterward, it could be a sign of a dying battery. It means that the battery has enough power to start but not enough to keep going.

The Check Engine Light is On

A check engine light can indicate a wide variety of problems, including issues with the fuel mix, alternator, and battery. It's not something you should ignore.

Your Car Battery is Misshapen

Batteries may swell and distort as a result of hydrogen gas buildup. Check the battery and look for anything that shouldn't be there and any signs that you have an issue.

There are No Dome Lights

If the dome lights are off and/or there is no chime when you insert the key, it suggests you have an issue with the electrical system and probably have a car dead battery.

You Have Dim Headlights

Are your headlights flickering? Are they dim? If so, your car battery could be on its last legs. If the headlights don't come on at all, there's a good chance that your car battery is dead.

The Battery Is Leaking

Leaking battery acid is always a bad sign. You may notice the leak when you look at the battery but can also detect a smell of rotten eggs stemming from the hydrogen sulfide.

You Have Corroded Battery Terminals

Batteries corrode, and this corrosion can seriously impact their lifespan. Look for a blue-colored powder on the battery terminal.

How to Start a Dead Battery

Your battery is dead, now what?

All is not lost, as there are a few ways you can jump-start your car and get back on the road.

You'll need a pair of jumper cables and another vehicle, either from a friend or a good Samaritan.

Position the vehicles so that they are facing one another but not touching. Turn the engines off, and shift them into Neutral.

Identify the positive and negative terminals on the battery. The negative will have a "-" sign or the word "NEG"; the positive will have the word "POS" or a "+" sign.

  • Clip a red jumper cable to the positive terminal on the dead battery. Attach the other end to the positive terminal of the working battery.
  • Attach a black cable clip to the negative terminal on the working battery; attach the other clip to an unpainted metal surface on the non-working vehicle.
  • Start the working car and leave it idle for a few minutes.
  • Start the dead car and wait for the engine to turn over.

If the engine doesn't start, leave it for a few minutes and then try again. Revving the engine on the running vehicle may also help to revive the dead car battery.

Once the vehicle is running again, detach the cables (starting with the negative clip) and keep the engine running.

If this process fails, it's time to call a mechanic and get some professional assistance.

FAQs About Dead Batteries

If you still have some questions about a dead or dying car battery, take a look at these FAQs.

What is the Cause of a Dead Car Battery?

There are a few potential causes for a dead battery, including:

  • You left the headlights on after turning off the engine
  • There is an issue with the alternator
  • The batter is corroded, weakened, or otherwise damaged
  • The car hasn't been driven for a long time

How Often Should I Replace My Car Battery?

You should get your battery replaced every four to five years, though you may need a new battery sooner than this if it's not properly maintained.

What Does a Car Battery Do?

In addition to starting the engine, a car battery powers all of the electrical components, including the headlights and dashboard lights. If you have a dead battery or a bad battery, you may experience issues with the whole system.

Can I Recharge a Dead Battery?

Yes, you can recharge a dead battery. Simply jump-start the vehicle using jumper cables and drive it around to replenish the charge. You can also use a battery charging system.

When Will I Need a New Battery?

If a battery voltage drops to 10.5V, it suggests that the lead plates are covered by lead sulfate. If it drops below this, the battery may suffer permanent damage as the lead sulfate forms into hardened crystals that can't easily be broken up.

If so, your battery will be completely dead and you may need to purchase a new one.

How Can I Make My Battery Last Longer?

Although your car's battery will typically last for up to 5 years, there are a few things you can do to get increase that lifespan:

  • Drive it frequently
  • Invest in a portable car battery charging system if you don't drive your car for long periods
  • Turn off all lights when leaving your car
  • Make sure the battery is tightly secured and stable
  • Watch out for corrosion on the battery terminals. Scrub corrosion away using baking soda and water.
  • Don't overuse electrical components when your car is idling.

Why Does My Car Not Start in Cold Weather?

In cold weather, the battery struggles to trigger the chemical reaction it needs to work. The cold can even drain all power from the battery. This is why you're more likely to experience issues and need jump-starting during the holidays.

It's not just cold weather that can harm your battery. Batteries are also prone to overheating and exposure to excessive heat will hasten the aging process.