10 Signs Of A Dead Car Battery (And What To Do About It)

Think you have a dead car battery?
If yes, what do you do about it?

In this article, we’ll answer those questions and also cover some car battery FAQs, including why a car battery dies and an easy solution to a dead car battery.

This Article Contains

10 Signs Of A Dead Car Battery
How To Jump Start A Dead Car Battery (Step-by-Step Guide)
7 Dead Car Battery FAQs

Let’s get straight to it.

10 Signs Of A Dead Car Battery

There are a few tell-tale signs that your vehicle’s battery is about to fail (or has failed).

Here’s a look at them:

1. No Response At Ignition

If your car doesn’t start when you turn the ignition key, it probably means the starter motor is getting zero power from a dead battery.

2. The Starter Motor Cranks But The Engine Won’t Turn Over

Sometimes, the starter motor might crank slowly, but the engine won’t start. This is a sign of either a dead car battery or a faulty starter.

If the starter cranks at the usual speed, but the engine still won’t start, you probably have a good battery, but there are issues with the fuel or spark plug.

3. Sluggish Cranking Times

Frigid weather reduces battery performance, so it’s normal for your engine to take longer to crank to life.

However, if there hasn’t been a temperature drop, and your engine still stutters before turning over, then you could have a weak battery, bad alternator, or starter issues.

4. The Engine Starts But Then Dies Immediately

Sometimes a vehicle starts, but instead of idling, the engine immediately dies. In this case, the battery’s charge may be just enough to turn over the engine.

However, the battery then fails, causing disruptions in the signals sent to the engine control module (ECM), and the engine then dies.

5. No Door Chime Or Dome Lights

Usually, when you open the vehicle door, the door lights turn. Similarly, there’s usually a chime that plays when the key is inserted into the ignition.

When these don’t work as they’re supposed to, a flat car battery is a usual culprit.

6. No Headlights Or Dim Headlights

Dim or flickering headlights, when coupled with an engine that won’t start, usually point towards a weak battery. This happens when the battery has just enough charge to power the headlights but not to crank the engine.

If the headlights don’t turn on at all, then you likely have a dead car battery.

7. The Check Engine Light Turns On

The Check Engine light turning on could mean many things, from the alternator not charging properly to fuel mix issues.

Don’t ignore it if this light turns on.
Get a mechanic to troubleshoot it ASAP.

8. Misshapen Battery

A swollen or bloated battery is an obvious sign of a bad battery, caused by a buildup of hydrogen gases. This happens when the vehicle’s alternator is overcharging, and the battery can’t dissipate the gases fast enough.

9. There’s An Odd Smell

If you notice your lead acid battery leaking, the fluid is likely not distilled water but battery acid.

Don’t touch it.
The leak is often accompanied by the smell of rotten eggs, which comes from leaked hydrogen sulfide gas.

10. Corroded Battery Terminals

Corrosion is one of the most common causes of shortened battery lifespans. It appears as a blue-green powder on the battery terminal and reduces the battery’s ability to receive a charge.

Now that you know the symptoms associated with a dead battery, what should you do about it?

How To Jump Start A Dead Car Battery (Step-by-Step Guide)

Jump starting is the most common solution for a dead car battery. If you don’t have a portable jump starter handy, you’ll need another running vehicle to act as the donor car and jumper cables to do this.

Here are the steps you’ll need to follow:

Ready The Jumper Cables
Position The Vehicles
Connect The Jumper Cables
Jump Start The Car
Detach The Jumper Cables
Keep The Engine Running

1. Ready The Jumper Cables

Always have a good pair of jumper cables in your vehicle, or you’ll have to rely on the donor car to have one.

2. Position The Vehicles

Position the vehicles to face each other, about 18 inches apart. Never let them touch.

Make sure both engines are off, gears are shifted into “Park” or “Neutral” (for both auto and manual transmission), and the parking brake is on.

3. Connect The Jumper Cables

Identify the positive terminal on the dead battery. It’s usually marked with a (+) symbol or the word “POS.” The negative terminal will have a (-) sign or the word “NEG.”

Now, do this:

Attach a red jumper cable clip to the positive terminal (+) of the dead battery
Attach the other red jumper cable clip to the positive terminal (+) of the donor battery
Attach a black jumper cable clip to the negative terminal (-) of the donor battery
Attach the other black jumper cable clip to an unpainted metal surface on the dead vehicle (like the metal strut that holds the hood up)

4. Jump Start The Car

Start the vehicle, and let it idle for a few minutes to charge the working battery.

Then, start the dead car.

If the dead car engine doesn’t turn over, let the working vehicle run for a few more minutes, then try again. If the dead car still doesn’t start after a second attempt, rev the running vehicle engine to raise alternator output and try to start the dead vehicle again.

5. Detach The Jumper Cables

Assuming you managed to get the dead vehicle running, don’t turn off the engine!

Detach the jumper cables, starting with each negative clamp first. Then remove each positive clamp.
Don’t let the cables touch each other while you do this, then close the hood.

6. Keep The Engine Running

Once the dead vehicle is up and running, drive it for at least 15-20 minutes to allow the alternator to recharge the battery. However, if your jump-start fails, the next best step is to call a mechanic for help, as you’ll probably need a new battery.

Now that you know how to jump-start your vehicle, let’s go over some FAQs.

7 Dead Car Battery FAQs

Here are the answers to some usual car battery FAQs:

1. What Causes A Dead Car Battery?

A dead car battery can come about because of a lot of different reasons, such as:

An electrical component (like the headlights) stayed on when the engine was off
The car hasn’t been used driven for a long time (a fully charged battery will slowly self-discharge)
The vehicle’s alternator isn’t charging the battery
Corroded terminals reduce the charge the battery can receive
Low temperatures during cold weather might have frozen the battery
Very high temperatures in hot weather might have weakened the battery

2. Why Does The Starter Motor Grind Or Click?

Ignition clicks combined with a no-start can indicate a bad starter motor or a problem with the starter solenoid. If there are grinding sounds with a no-start, it could be the sound of the starter motor teeth misaligning with the flywheel (or flexplate) teeth.

Continuous cranking in this condition can result in more serious, costly damage.

3. Why Does The Battery Die Again After A Jump Start?

Here are some reasons why your car battery won’t hold a charge after a successful jump start:

The car wasn’t driven long enough for the battery to recharge fully
The vehicle charging system has a problem, like a bad alternator or voltage regulator
An electrical system was left on, draining the battery
The battery is too old and just can’t hold a charge

4. Can I Recharge A Dead Car Battery?

Often, a “dead car battery” simply means that it’s fully discharged and the voltage is below functional 12V. You can jump-start the dead vehicle and drive it to let the alternator replenish the battery charge.

Alternatively, you can attach the dead battery to a battery charger.

If the car battery voltage is under 12.2V, you may want to use a trickle charger to avoid battery overcharging or overheating.

Otherwise, call roadside assistance and let a mechanic deal with your dead car battery.

5. When Is A Dead Car Battery Truly Dead?

A car battery is considered fully discharged at 11.9V. However, if the voltage drops to around 10.5V, the lead plates are likely almost entirely covered by lead sulfate.

Discharging below 10.5V can permanently damage the battery.

Additionally, if the battery is left dead, the lead sulfate eventually forms into hardened crystals that can’t be broken up by alternator current or a regular car battery charger. At this point, you may have to get a new battery.

6. What Are The Signs Of A Bad Alternator?

You could have a faulty alternator if your vehicle:

Headlights are dim or overbright due to inconsistent alternator current to the battery
Has trouble starting or frequently stalls
Has a malfunctioning electrical component as the alternator isn’t supplying enough current to the battery
Has whining or growling sounds from a misaligned alternator belt

7. What’s An Easy Solution To A Dead Car Battery?

Finding a dead car battery under your hood can be pretty stressful, but don’t let it get to you. An easy solution is to call a mechanic to troubleshoot issues or simply attach a new battery.

Fortunately, all you need to do is contact a mobile mechanic like AutoNation Mobile Service!

What’s AutoNation Mobile Service?
AutoNation Mobile Service is a convenient mobile vehicle repair and maintenance solution. Here’s why you should opt for us:

Car battery replacement and repairs can be made right in your driveway
Expert technicians execute vehicle inspection and servicing
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Competitive, upfront pricing
All maintenance and fixes are conducted with high-quality tools and replacement parts
AutoNation Mobile Service offers a 12-month | 12,000-mile warranty for all repairs

Fill this online form for an accurate estimate of the cost of your battery repairs and maintenance.

Final Thoughts

Keeping a check on your car battery is an integral part of car care. It’s always a good idea to get your battery tested annually when it’s around the 3-year mark to make sure everything’s fine. And if you do notice any problems, you can always rely on AutoNation Mobile Service to deal with any battery issues.