As someone who’s spent years tinkering under the hood, I’ve come to know that the first measure of the dependability of a vehicle lies in its battery. A weak or dead car battery can either leave you stranded somewhere, or else make you late for work, school, or other appointments.
But how do you know when it’s time to replace it?
Today, let’s take a look at the 3 most common ways your car’s power supply might be hinting at retirement (hard-starting, usage, and physical appearance) and how to decode the clues it’s been giving you. We’ll see if your weak battery has given up the ghost or not.
Let’s get started.
3 Signs That You Have A Truly Dead Car Battery
There are a few signs that you can generally rely on to indicate that your vehicle needs a new battery soon. Those signs involve: problems starting your car, batteries that have been used for too long or not at all, and signs of physical damage on the battery and its casing.
Let’s take a deep dive into each of those signs:
#1 Problems Starting Your Car – Weak Battery
A car in excellent operating condition (including its battery) will start as soon as you turn the key in the ignition. At most, like on cold mornings, you might need an extra second or two for that to happen.
However, should the car take more than 2 seconds of cranking to start, that’s a common telltale sign that you’ve got battery problems. However, it’s also possible that you have an alternator or connection problem, but those issues are covered in another article.
Assuming the alternator and connections are fine, here are the main symptoms of a failing battery:
- An engine that won’t crank at all
- An engine that cranks very slowly while turning the key
- A car that often needs jumpstarting to start (i.e. can’t reliably start on its own)
Starting the engine suddenly becomes a challenge because your vehicle’s battery is too weak or is approaching the end of its lifespan and is about to die out.
If the battery is completely dead and has no charge at all, you will find that the engine won’t even crank a little bit. This is further confirmed when none of the lights or other electrically-powered car components will work.
Related: Does a Car Battery Charge When Idling?
#2 The Battery Has Been Overused….Or Underused
Another clear indicator of whether or not you need a new battery is its usage patterns.
Underuse:
For example, some people underuse their car batteries by leaving their car parked for weeks or months without ever starting the engine. But with each passing day, those batteries naturally lose a little bit of their charge.
Most car batteries can last approximately 2 weeks without charging (via the engine’s alternator). However, left unused, the battery continues to discharge until one day, when it dies completely.
Unfortunately, a dead car battery that’s been left without a charge for several months or years might never be able to recharge, making it completely useless.
So, if that sounds like the battery in your car, then you’d be better off investing in a new replacement.
Read: How Long Can a Car Battery Sit Unused?
Overuse:
However, the opposite conditions are also just as unhealthy for a battery.
That’s right! Overusing a car battery will wear it out faster, and you’ll likely need a new replacement soon than normal.
A car battery is just like any other battery in that it has a limited number of charges and discharges in it. So, the more times you’ve drained and recharged the battery, the closer it gets to being worn out.
Overusing a car battery can mean one of two things:
- A battery that is used for too long: A typical car battery can last for 3-5 years. By the end of that period, the car would have used that battery so many times that it reaches the natural end of its lifespan.
- A battery that’s been drained too often: Suppose the driver habitually uses the car’s electrical power to charge gadgets and appliances while the engine is off. In that case, the battery will discharge until it’s empty, without the engine and alternator recharging it simultaneously. Draining the battery continuously will wear it out much faster, causing you to need a replacement sooner than usual.
So, suppose you know that your car battery has been underutilized or overused. That may be an indicator that you need to purchase a replacement soon.
Read: Why Car Won’t Start With New Battery?
#3 The Battery Has Physical Damage
The third and final sign of of a dying or dead car battery is when you see physical damage on the battery and its casing.
Under normal conditions, car batteries should look from the outside like a rigid plastic box with two electrodes on the top. However, when you look at a car battery under the hood, you see the outer shell. That shell safely houses the battery’s cells, electrolytes, and other components.
As long as the battery’s case maintains its shape and none of the fluids inside come out, you can rest assured that it’s still in good condition.
However, any of the following visual signs mean that you’ll have to buy a new battery immediately:
- Cracks in the battery’s case
- Swelling or bulging of the battery’s case
- Leaks of the battery’s electrolytes
- Rust or corrosion on the electrodes on top of the battery
Bear in mind that the car battery might still function despite these physical signs of damage. However, they’re caused by internal problems that make the battery very dangerous to continue using.
If you see any of those signs, disconnect the battery and do not start your car. Instead, call someone to replace the battery wherever your car is parked or get a tow truck to move your vehicle.
Starting the engine and driving your car while the battery is damaged is incredibly dangerous to you, your vehicle, and other road users.
Read: Why Car Won’t Start but Battery Is Good?
How Long Do Batteries Last?
A car battery will typically last around 4 years. The precise lifespan can differ between cars and owners, depending on their usage patterns.
However, you can maximize the lifespan of your car battery by:
- Cleaning the battery case regularly
- Starting the engine regularly, even if you’re not driving the car
- Checking the battery’s voltage and recharging it if you’re not using your car
- Turning off electrical and electronic car components when the car’s not in use
These simple steps will help prevent excess wear and keep your car battery fully charged. In doing so, you’ll maximize the battery’s lifespan and get the most value out of it as possible.
Read: Why Car Battery Terminals Corrode?
What Causes Batteries To Fail?
Now let’s take a look at some of the causes of a dead car battery in more detail, and how to determine which one might apply to yours.
Age: The Battery Killer
I’ve seen my fair share of batteries weathering the sands of time. Age is more than just a number here. Your car battery, unlike a fine wine, doesn’t age gracefully. On average, these powerhouses clock out after 3 to 5 years.
A clear sign of a weak battery is a frequent slow cranking of the engine when you turn the key. If your vehicle groans more than hums when you attempt to start it, age might be the culprit. Even if you’re meticulous with maintenance, any battery will eventually bow out.
Diagnosis Tips:
- Check the Age:
- Flip open the hood and decipher the manufacturing date on your battery. If it’s pushing five, it’s time to think new.
- Dimming Headlights:
- When your headlights lose their usual brightness, it’s the battery signaling fatigue. The telltale flicker shouldn’t be ignored.
Weather: Dead Battery Culprit
Over the years, I’ve learned to respect the impact of Mother Nature on all things mechanical. In the case of a battery, extreme temperatures are a silent adversary, chipping away at its health. In the scorching heat, fluid evaporation becomes the enemy. When winter knocks, chemical reactions slow down, strangling your battery’s vigor.
Diagnosis Tips:
- Corrosion Check:
- Pop the hood and scrutinize the battery terminals for white, ashy residue. Corrosion signals nature’s toll.
- Slow Engine Crank:
- Winter brings slow cranks. In summer, the heat could be overwhelming. The engine’s struggle speaks volumes.
Parasitic Drains: Sucking The life Out Of Your Battery
Parasitic drains are small power “leaks” that slowly and quietly draw electricity while you’re away and unaware. These stealthy energy vampires drain your battery when the engine’s asleep. It might be a malfunctioning component or just a courtesy light that overstays its welcome.
Diagnosis Tips:
- Multimeter Magic:
- Equip yourself with a multimeter to measure electrical drain when the car is turned OFF. Over 50 milliamps? Investigate.
- Odd Electrical Issues:
- Midnight honks or radio tunes on their own? It’s not paranormal; it’s likely a parasitic drain revealing its presence.
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Knowing When To Say Goodbye To A Dead Car Battery
Diagnosing a battery’s last hurrah requires a toolkit of methods. Let’s delve into the tools that help determine the cause of a weak or dead car battery:
1. The Jumpstart Test:
- If your car is needing a jumpstart often, the battery might be calling it quits. However, a failing alternator can give similar symptoms.
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2. Voltage Check:
- Grab a voltmeter, attach it to the terminals, and crank the engine. If the volts drop below 10, the battery is whispering its final words.
3. Visual Inspection:
- A bloated battery case or mysterious odors are silent cries. Bloated means internal issues; odors may signal leakage.
4. Hydrometer Happiness:
- For non-sealed batteries, a hydrometer measures electrolyte specific gravity. If it’s uneven between cells, retirement is on the horizon.
5. Advanced Diagnostic Tools:
- Auto shops offer free diagnostics. A load test assesses the battery’s capacity. Sometimes, experts unveil what our eyes miss.
Final Thoughts
The battery in your car is a crucial component for starting the engine and keeps your electronics powered. Unfortunately, most people choose the cheapest car battery they can find because they assume it’s less important than other components.
However, investing in a slightly pricier battery with higher-quality components can give you more peace of mind that the battery will last longer, as well as handle cold starts better.
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