Is Your Car Battery Completely Dead? Here are The Most Common Reasons

The average car needs two things to keep it running all the time: fuel and a battery. Thanks to the emergence of electric cars, fuel isn’t even necessarily all the time anymore. But a battery definitely is, and when your car battery is completely dead, you could be left stranded.

A typical car battery can last you three to five years. However, there are a number of things that can drain your battery or cause it to perform worse than you would like it to. When that happens, you’re going to need either a jump-start from a portable starter or a friendly Samaritan, or a new battery all together.

Let’s take a look at some signs and symptoms that your car battery is completely dead, what might have caused it in the first place, and finally what you can do to get your car moving again.

What Caused My Car Battery to Die?

If you get into your car in the morning and find that the battery is dead, it’s going to be pretty frustrating. If this is the first time it’s happened, there may be a simple explanation of what’s going on. However, if this is happening regularly, then something more serious is going on.

• You left something on. This is harder to do in modern cars. Many newer vehicles have alarms to let you know that the lights are on, for instance. But not all of them, and there can be other causes as well.

Leaving your headlights on is the most common thing that you can accidentally leave on to drain your battery. However, it’s possible that some other electronic devices in your car such as a phone plugged in, or some aftermarket sound systems can continue to drain the battery even after you’ve turned the car off.

• Bad connections. Your battery is connected to the rest of your car at the positive and negative terminals which have clamps and cables attached to them. These can come loose on their own.

It’s also a possibility that the terminals in your battery could have a buildup of corrosion. This is usually a flaky white or grey substance around the terminals themselves. Your battery will be unable to transmit the correct amount of power through this corrosion, which can make it impossible to maintain the power needs of your vehicle.

• Parasitic power loss. This is similar to what happens when you just forget to turn your headlights off. The difference here is that this is usually the kind of thing you wouldn’t think of and didn’t plan to leave on in the first place.

Parasitic power drains come from electronic components that were supposed to turn off but didn’t for some reason. Things like your interior lights, which come on when you open a door. If the door doesn’t close properly, the lights may stay on and drain the battery.

• Quick trips. It surprises many drivers to find out that the way they drive their car can have a profound effect on how their electrical system works. In order for your battery to maintain the charge, the alternator has to keep recharging it as you drive. 

If you only drive your car for extremely short trips, you could be limiting your alternator’s ability to keep your battery charged. This will get worse as your battery gets older.

• Cold weather. Batteries perform worse in the extreme cold, just as a matter of physics. Batteries produce power thanks to a chemical reaction that occurs inside of them. These chemicals can’t move as freely in the cold weather, which slows down the reaction that produces electricity.

If you live in a cold enough climate, you probably noticed that your car struggles a bit to get started on very cold days. This is the reason why, because your battery is having difficulty in the low temperatures. If it gets cold enough, and your battery is already a little older, you may not be able to start it all until it warms up.

• Bad alternator. Your battery and your alternator have to work together to power the electronic components of your vehicle. While all the initial charge comes from your battery, it’s your alternator’s job to maintain the electronic systems while you’re driving. That includes keeping your battery charged.

If your alternator dies, then it becomes the sole job of your battery to maintain the electrical systems in your vehicle. A car battery only has the ability to run a car on its own without the aid of an alternator for about a half hour at the most, but probably closer to 10 minutes.

• Old battery. As we said, a typical car battery is only going to last for 3 to 5 years. If your battery is nearing the end of its life span, then the charge it’s holding is going to be inconsistent at best or incapable of managing the needs of your car at worst.

A properly charged car battery will have about 12.6 volts registering on a multimeter if you check it. 12.4 volts to 12.5 volts is perfectly feasible to keep your car running. When it drops down to 12.3 it’s going to be dangerously close to not being able to maintain your power needs.

A 75% charge in your battery will read as 12.4 volts. If your car battery drops down to 12 volts, it means you only have a 25% charge left. At 11.9 volts, your battery is completely discharged. 

Signs and Symptoms of a Bad Battery

If your battery didn’t die because you accidentally drained it overnight, there are typically some signs you can be on the lookout for to let you know you have a problem. Any of these should give you some time to repair by charging your battery or replacing it with a new one.

• Dim headlights. It can be sometimes tricky to figure out if it’s the battery in your car or the alternator that’s giving you trouble. One way is to check the headlights. If the headlights are dim when you first turn the ignition but then get brighter once the engine turns on, you have a problem with your battery.

Before your alternator has a chance to take over, your battery is running the electronics in your car. So, when you first try to start your vehicle, the headlights are running on battery power alone. If they get brighter when the engine is going that means the alternator has taken over and is providing adequate power for them.

• Slow cranking. If you’re finding that starting your car is taking a little longer than usual and getting the engine to crank seems more drawn out than normal, it’s likely that a bad battery is the culprit and is not able to provide the immediate, full charge that your starter needs to get the car going.

• Clicking sounds. This is one of the more infamous signs of a battery problem. When you turn your key or press the ignition button, a clicking sound is what you get instead of the car starting. Sometimes the car will start after a few clicks as well.

The clicking is likely from the starter not having sufficient power to get your engine running. The clicking is the sound of your starter attempting to get your engine moving but not having the power to do so.

• Backfiring. There are a number of reasons your car could start backfiring, but a failing battery is certainly one of them. If your battery is working incorrectly, it may cause unexpected sparking. When this happens, you may end up with sparks igniting your fuel mixture at the wrong time, which can cause backfires.

• Corrosion. This is the same issue we mentioned earlier as a cause, but it’s also a symptom. If you take a look at your terminals and see a crusty substance on them, then you know your battery has an issue with corrosion that is going to need to be cleaned up.

Most cases of battery corrosion aren’t too bad, but sometimes it can get extremely out of hand and the corrosive substance can spread across the top of the battery. If it gets bad enough, then you simply can’t draw any power at all for the battery.

Luckily, cleaning corrosion off a battery is fairly easy and all you really need to do is remove the negative terminal first followed by the positive terminal, then use a stiff brush and a paste made from baking soda and water to scrub away all the corrosion until they look good again.

The Bottom Line

If your car needs to have the battery replaced is going to set you back somewhere between $50 and $200 depending on the type of battery you buy and whether you need a mechanic to install it for you. 

Like we’ve said, a new battery is not something you should need unless your old battery has been around for about three to five years already. If it dies earlier than that or you find that your battery needs more frequent jump-starts even though it’s still pretty new, you may need to look elsewhere for problems.

It’s possible you have some kind of parasitic draw on your battery, or your alternator is failing, and your battery is struggling to make up the difference for it.