Last Updated: 06.04.2022

It’s a good morning. You are ready to go to work, so you head to your car, start the engine, and voila—a dead car battery! It is a nightmare no one would like to experience! 

Good thing, it is something you can avoid by diagnosing the problem early and doing the necessary fixes. To do this, you need to be aware of bad battery symptoms! 

From slow cranking to physical defects, watch out for different signs that your battery is about to give up. Diagnosing the problem early means that you can quickly implement the right solution. Read on to find out some of the red flags to watch out for! 

10 Bad Battery Symptoms

car battery positive terminal covered

You don’t have to be a mechanic to identify a bad battery. This section talks about some of the things that can happen before your battery gives up. 

Slow Crank 

Many of you are familiar with the sound of your car when starting. When you notice that it is slower than usual and it is making a weird sound, the battery can be the culprit. 

Your car can end up being more sluggish when you turn the key if the battery is about to die. This is one of the easiest red flags to spot, so make sure to immediately charge the battery or look for any other potential solution.

Dim Lights 

The lights of your car are powered by a battery. Whether it is the interior or exterior lights, when they dim, take it as a sign that you may a bad battery. Sometimes, the interior lights may also not turn off even when the doors are shut.

If you see that the headlights are weaker but the battery is fully functional, you might want to look at other things. For instance, it can be because of poor electrical connections. Alternatively, it might also be because the bulb itself needs a replacement. 

Check Engine Dashboard Light

vehicle dashboard indicators

A lot of cars are smart enough to spot common problems without a trip to the mechanic or you performing a lengthy diagnosis. By quickly looking at the dashboard, you will know the issue. 

If the Check Engine light is on, then it can be because your battery’s juice is trickling. Nonetheless, take note that this can be indicative of many other things, such as problems with the sensors, modules, air delivery, ignition, and transmission. 

Electrical Problems 

As soon as your car battery goes bad, electrical problems will be apparent. They go beyond flickering lights. The radio may end up not working as it should. It also affects the heating and cooling systems in your vehicle. 

Any problem with the battery will affect the electricals that connect to it. Nonetheless, do not immediately blame the battery, as it can be the component itself that is malfunctioning. 

Clicking Sound 

Hearing an unusual noise from a car instantly sends some people into a panic. Keep calm and start diagnosing the problem so you can fix it immediately. Among others, it can be one of the many bad battery sounds. 

When there is a rapid clicking noise, the issue can be electrical, which is why you can link it to a battery or alternator. As you turn the ignition, the battery sends a signal to the starter solenoid. When the battery fails to do so, you will hear a click. 


combustion fumes coming out of car exhaust pipe

The combustion of your car’s air-fuel mixture can make the engine backfire. It produces a loud sound and exhaust fumes. Aside from wasting fuel, it also damages the engine, resulting in costly repairs! 

While there are many reasons why the engine backfires, one of the most common issues is a bad battery. Your battery can be low. Confirm this by checking the voltage or by performing a quick load test. 

Low Battery Fluid 

A car’s battery fluid is a mixture of distilled water and sulfuric acid. It generates electricity for the battery to work as intended. Once the fluid is low, this is another sign that the battery has a problem. 

Some will have a clear indicator, so you will know if it is time to top off with water. More so, you can also opt for maintenance-free batteries, so you won’t have to think about fluid replacement. 

Bad Smell 

Another common symptom of a failing battery is a bad smell, which is often reminiscent of a rotten egg. This is indicative of a sulfur leak, depending on the type of battery that your car has. It can be due to the production of hydrogen sulfide gas, which causes the fluid in the battery to boil or overheat. In most cases, it is followed by smoke. 

Bulging Case

battery in the engine room

Regular battery inspection is a must to ensure its peak condition. A bulging case is a sign that there is a problem. Swelling is a result of excessive current, which causes gas and heat to build up. 

Additionally, it can also be because of old age. Whatever the culprit is, replace the battery when needed to avoid the problem from worsening. 

Rust and Corrosion 

One of the easiest ways to tell if your battery has gone bad is to look at it. If you see rust and corrosion, especially in the terminals, take this as an indicator that something is wrong. It could be because the battery is old. 

Possibly, there is a leak and exposure to external elements that cause the battery to degrade. A clear film might develop on the battery case, which can make the engine sluggish. 

Tips and Tricks to Prevent Car Battery Problems 

Now that you know the tell-tale signs of a bad battery, below are some of the best things to do to prevent the problem. 

Keep the Battery Clean 

Dust and dirt accumulate on the battery over time. It can lead to a short circuit, which makes the battery dead. Rust and corrosion are also common problems, especially on the terminals. Regular cleaning is necessary to keep the battery in peak condition. 

Check the Voltage Regularly 

By checking the battery’s voltage at least once a month, you can be confident of its optimal performance. Investing in a voltmeter is a good idea. At the minimum, the battery should have at least 12.7 volts. If it is lower, charge the battery. 

Add Distilled Water 

As you inspect the battery, pay attention to the fluid level. If it is low, add distilled water until you cover the plates. Do not use tap water since it has trace minerals that negatively impact the battery’s performance.

Unplug Appliances 

Especially for long-term car storage, unplug all appliances, which include radio, cameras, and GPS navigators. Leaving anything plugged can drain the battery. Make sure as well that you turn off all the lights. 

Determining If the Problem Is the Battery or Alternator 

The battery and alternator are two of the most important parts of your car. They complement each other, making it difficult to identify which one is the problem. As you turn the engine on, the alternator charges the battery and fuels the electrical system of your car. When the car is off, it is the battery that powers the electrical system. 

If you are having a problem starting your car or if your car stopped running and won’t start, there are two potential issues: the battery or the alternator. It is tricky to pinpoint the exact cause. However, one of the best things to do is to jumpstart your car. This fix will work if the battery is the problem. If it does not, then you have to look at the alternator. 

The weather can also be a quick indicator of the problem. If it is too cold, a car battery may not work, so you can assume that such is the issue and not the alternator. 

To confirm if the alternator is bad, start your car. Unplug the positive terminal of the battery. If it stops, then it is safe to assume that you have a faulty alternator. 

In most cases, the signs of a bad alternator and battery are the same, which makes it confusing to determine the problem. However, in many modern cars, there is a separate warning light for the battery and alternator, so you can see which one isn’t working. You should also know how long it takes to change a car battery, in general. 

Final Thoughts 

Slow crank, dim lights, backfiring, and a bulky case are some of the most common bad battery symptoms, as we talked about in this article. A quick look at the dashboard is a great way to determine if the battery is the issue. In most cases, you have to take a closer inspection of the battery and evaluate your car’s performance to determine the problem. 

Do not wait before it is too late! As soon as you notice the symptoms of a failing battery, act immediately. Some of the quick fixes include charging, cleaning, and replacing the battery. The failure to fix it the soonest will result in a dead battery, which can be annoying, especially if it happens when you are on the road.