5 Reasons Your Car Battery Is Smoking (And What To Do)

If your car battery is smoking, one thing you know for certain is that there’s definitely a problem. In this article, you’re going to find out the 5 most common reasons your car battery could be smoking, as well as what you should do when it happens!

So keep reading to find out everything you need to know!

What Causes A Car Battery To Smoke?

If your car battery is smoking, then the first thing you’ll want to do is try and figure out the cause. Here are the 5 most common causes behind why your battery is smoking.

It’s Being Overcharged

In a lot of cases, the most common cause of your battery smoking is because it’s being overcharged. When your battery is being overcharged, the cells inside release the excess pressure, so smoke ends up coming out. This is actually the same reason batteries have been known to explode. The gas that comes out is both highly toxic and highly flammable.

There’s A Problem With The Alternator

While you might be overcharging a battery with a charger, overcharging can also occur when there’s a problem with the alternator as well. For example, if the voltage regulator isn’t working correctly, then it can result in too much energy being pumped into the battery.

Alternators should produce between 13.7 – 14.7v, so if you notice that the alternator is producing more than this, then you can have some level of certainty that the alternator is causing the problem.


Another reason that batteries can end up smoking is once they start to overheat. If you’ve noticed that the smoking happens during hot days, or if you live in a hot climate, then this could be the cause of the smoke. In fact, when the weather gets too hot, some people have even had their batteries explode in the car.

During hotter times, the electrolytes in the battery can evaporate completely. When this happens, smoke and steam are produced until the electrolyte solution has emptied completely.

Dead Battery

Sometimes, the smoke can occur once the battery has died. So if you can’t remember the last time you bought a new battery for your car, then the chances are the battery may have died.

Your dead battery may have even been able to start the car one last time before it died completely. However, if it’s smoking now, then the battery may have died completely.

Connection Problems

Sometimes the battery may be smoking because there’s a connection problem or internal shorting occurring inside it. One of the easiest ways to solve connection problems is to make sure the terminals are tightly screwed. While, in some cases, it might not fix the issues, it can often reduce the chance of shorting occurring.

Another reason smoking could occur in response to a connection problem is when the positive and negative plates have come into contact with each other.

Engineer with oil on his hands holding a car battery tight

Why Could Your Battery Be Steaming?

If your car battery is steaming, then it means the electrolyte solution inside the battery is boiling. In rare cases, this can eventually cause the battery to explode, which will cover everything under the hood in acid. So if you notice that the battery is steaming, it’s best to turn your car off and park it in the shade or somewhere cold.

Why Does Your Battery Smoke When Charging?

If you notice that smoking occurs when the battery is charging, then it means the battery is being overcharged. You should immediately turn the charger off when this happens to help reduce the chance of irreversible damage occurring to it.

One of the most common causes of overcharging in the battery could be a problem with the alternator; however, if you’re using a charger, then it could also mean that the charger is faulty as well. When you’re charging your battery, the output should be between 13.7v – 14.7v. Anything more than this can cause damage to the battery permanently.

What Should You Do When The Battery Starts Smoking?

When the battery of your car is smoking, the first thing you’re going to want to do is to turn the vehicle off as soon as possible to prevent any further damage from happening to the car. Once you’ve done this, you should then move away from the car, as the fumes from the battery are not only highly flammable but they’re also toxic as well.

If possible, you should also try parking your car in a cool location to prevent the battery from overheating due to environmental problems.

Once you’ve done this, you should then call an expert to get their advice and take it to a mechanic if possible. Remember, a smoking battery is never a good sign, so you’ll need to get it fixed ASAP.

How To Prevent Car Battery From Smoking

Now that you know why your car battery is smoking, here are all the things you can do to prevent it from happening in the future!

Keep Your Car Battery Clean

The dirt and grime that accumulates on a car battery can cause it to overheat, leading to smoke. Regularly check the terminals of the battery and clean them with a wire brush or baking soda mixture to prevent dirt buildup.

Check The Connections

Loose connections can cause arcing, leading to smoke. Examine the terminals and all connection points for your car battery and tighten them as necessary.

Use The Correct Size Battery

Using a car battery with the wrong size can lead to smoke. Measure your current battery and make sure you purchase the same size for a replacement.

Check The Fluid Levels

Make sure your car battery has enough electrolyte fluid. Low fluid levels can cause the battery to overheat and generate smoke.

Replace An Old Battery

When a car battery reaches the end of its life, it may generate smoke or even catch fire. Have an old car battery checked by a professional and replace it as soon as possible. If your battery is older than three years, consider replacing it to avoid any safety risks.

Charge The Battery Correctly

Overcharging or undercharging your car battery can cause it to overheat, leading to smoke. Make sure to charge the battery correctly and have it checked regularly for any issues.

Avoid Using Cheap Chargers

Cheap or fake car battery chargers can be dangerous and cause your battery to overheat, leading to smoke. Make sure you use a quality charger that meets the specifications for your car battery. If you suspect a faulty charger, replace it immediately.

Don’t Let Your Car Sit For Too Long Without Starting It

If you let your car sit for too long without starting it, the battery can become drained and overheat, leading to smoke. Try to start your car at least once a week on average, even if it’s just for a few minutes. This will help keep the battery charged and avoid any overheating issues.

Check Your Battery’s Voltage Regularly

Check the voltage of your car battery regularly to make sure it’s at the right level. If it drops below 12 volts, recharge it even if it hasn’t become completely drained. Low voltage can cause the battery to overheat, leading to smoke.

Be Aware Of What You Plug Into Your Car

Many devices that use a cigarette lighter socket can draw too much power from the battery, leading to smoke. Avoid using low-quality chargers and make sure to unplug any device when you’re not using it.

Don’t Overcharge The Battery

Overcharging the battery can cause it to overheat and smoke. If you charge your car battery with a charger, make sure to follow the manufacturer’s instructions and unplug the charger when it’s finished.

Make Sure Your Electrical System Is Functioning Properly

A malfunctioning alternator or an electrical system with bad wiring can cause the battery to overheat and create smoke. Have a professional check your car’s electrical system regularly to make sure it is functioning properly.

Check The Environment Around Your Car Battery

Make sure there is enough air circulation around your car battery and that it is not in direct sunlight. Heat buildup from the sun or a lack of ventilation can cause the battery to overheat and smoke.

Avoid Short-circuiting The Battery

Short-circuiting a car battery can cause it to overheat and generate smoke. Make sure the battery is properly insulated when you’re working on it, and use caution when handling the terminals.

Avoid Using Accessories Too Often

Using accessories such as heated seats or lights can draw too much power from the battery, leading to smoke. Avoid using accessories too often and make sure to turn them off when you’re done using them.

Never Attempt To Fix A Damaged Battery

If a car battery is damaged or leaking, never attempt to fix it yourself. This can be dangerous and cause the battery to smoke or even catch fire. Have the battery checked and replaced by a professional if necessary.

Replace The Battery When Needed

If your battery is older than three years and showing signs of wear, it’s best to replace it. Old batteries can cause fires or other damage. Have a mechanic inspect the battery and replace it if necessary.

Inspect The Battery Regularly

It’s important to inspect your car battery regularly for any signs of wear or damage. Look for cracks, bulging, corrosion, or other signs that the battery may need to be replaced. Have a professional inspect it if you suspect any issues.

Be Aware of How You Store Your Car Battery

Properly storing your car battery can help prevent it from overheating and smoking. Store the battery in a cool, dry place and make sure it is properly insulated. Avoid storing the battery in direct sunlight, as heat buildup can cause it to overheat.

Can You Drive A Car With A Smoking Battery?

You absolutely should not drive a car when the battery is smoking. Not only do you risk causing more damage, but you also risk killing the battery completely. So the next time you try to start your car, it just won’t work.

As well as this, when the car battery is smoking, it means that some of the flammable gases are leaking out, which in rare cases can result in the battery exploding.

Can A Bad Battery Cause Car Issues?

While smoking car batteries are unlikely to cause a lot of damage to the rest of the car, it doesn’t mean it’s impossible that they won’t. For example, they might end up causing electrical issues in the rest of the car under certain circumstances. As well as this, if the battery explodes, the rest of the engine could be coated in battery acid, further causing damage.

Are Smoking Batteries Dangerous?

If the fumes of the battery are breathed in too much, then you may notice side effects such as nausea and sickness. The fumes coming from them are extremely toxic and definitely shouldn’t be breathed in. As well as this, the smoke is also highly flammable, so if there’s a spark near them, it could result in the battery exploding.


As you can see, in most cases, the reason that your battery is smoking is that it’s being overcharged. However, connection problems and overheating can also be the causes behind it as well. But, the most important thing to remember is that whenever the battery is smoking, the best thing to do is turn the car off, move away and call a mechanic!

If you liked this article, make sure you check out the rest of the website. Otherwise, have a great day!

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