5 Symptoms of a Bad Car Battery

Last Updated on January 7, 2020

As you turn the key to start up your vehicle’s engine, the battery of the vehicle produces an electrical current which goes into the ignition system and starter motor.

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If another current is needed which the alternator cannot provide, then the battery will provide this extra current. After all, the battery is the vehicle’s reservoir of electricity.

The lead-acid storage battery, aka the automotive battery, generates the voltage needed to start the vehicle and then delivers it. The action of this electrochemical device is reversed as the vehicle runs the battery. As a result, the battery gets recharged so it can continue to service the vehicle for a few years.

Top 5 Bad Car Battery Symptoms

If your battery is starting to go bad or fail, there are some recognizable signs to look out for. Once you start to experience these symptoms, you should consider replacing your battery right away.

Otherwise, a bad battery can cause extra problems for your vehicle and at the very least, frustration for you at the worst time.

#1 – Warning Light for Battery

car battery light on while driving

On the dashboard, you should see a battery warning light that may illuminate. The light should be shaped to look like a battery and it will turn on if the battery is not properly charging or the battery has some internal issue.

Often, this warning light comes on when there is an issue with the alternator or any area of the electrical system. The best thing you can do when this light comes on is to test the voltage of both the alternator and battery or take it to the mechanic and have them do this for you.

Related: Difference Between a Dead Battery and Bad Alternator

#2 – Engine is Slow to Crank

car keys in ignition

If it takes longer than usual to start your car, this is an early warning sign that your battery is almost dead. You’ll experience a long whirr as you try to start the car. The next thing you’ll know, the electronics of your vehicle will not power on either.

A failed battery is often the cause of a slow engine crank. So, if your car still eventually starts after it whirrs for a little bit, use a multimeter to test the voltage of the battery to make sure it’s not starting to fail. Or take your car to the nearest auto parts store or repair shop to have them test it.

If you’re getting too low of a voltage, get your battery replaced before all the electronics in your vehicle stop working or you get stranded somewhere and need to jump start your car.

Aside from the whirring, you could also verify the condition of some types of batteries by checking the level of battery fluid and seeing if it’s low. You may also have a battery case which is swollen too. Of course, This smell is the result of sulfur leaking out of the battery. This causes the cable connections to have corrosion form on them. This corrosion needs to be cleaned prior to starting the vehicle.

Related: Best Portable Battery Jump Starters

3) Rotten Egg Smell

One of the most easily recognizable signs is the smell of rotten eggs after you open the hood. Most car batteries contained a combination of sulfuric acid and water. When the battery starts to get worn out, both elements of the mixture could evaporate and cause problems for the rest of the mixture.

As a result, the battery will begin to boil from overheating and cause that horrible rotten egg smell to fill the air around it. You may even see smoke come out if it gets bad enough.

4) Problem With Electrical Components

high beams not working

The battery of a car needs to do more than just power the engine. It also has to power the electrical components of the car as well. These days, cars are loaded with all kinds of electrical components and accessories.

You have headlights, power seats, heated seats, power windows, dashboard lights, stereo, navigation, windshield wipers, and other power hungry features. These all function from the power of the battery.

If they stop working or don’t work as well as they should, then that is usually a sign of a weak car battery.

See Also:  Tips for Car Battery Maintenance

5) Bloated Battery Case

car battery bloated

The battery in an automobile exists inside of a box. This battery goes through a chemical reaction to provide power to the vehicle. However, there could be situations where the chemical reaction doesn’t perform as it’s supposed to.

Perhaps there is too much cold or heat around the battery which is causing this to happen. If that’s the case, there’s a rare scenario where the sides of the battery (which are normally flat) will start swelling up. This is often the case for people who live in colder regions and don’t drive their vehicles very much.

What happens is their car batteries begin to freeze up and then swell because their vehicles haven’t been driven in a long time and the battery hasn’t been used. This will result in the battery needing to be replaced because once the battery swells, you might as well kiss it goodbye because it’s dead.



  1. I have an Acura r l 2002 I just replace the battery the car has had a problem starting up since I got it it seems when I turn the ignition sometimes it starts and sometimes it doesn’t but I noticed when it first rained it had a problem starting up more than the other days so I’m going to replace the coil packs and start from there since I just replace the battery I know that there is an ignition wire in there that could possibly be the culprit but I’m not sure might you have any advice for me I would greatly appreciate it thank you


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