Can a weak battery cause a car to run rough? 5 symptoms & causes revealed

By Arif

Tightening of battery terminals

Have you been noticing a rough ride from your car? It is not unusual for a car to go rough but what matters is the reason behind it. Can a weak battery cause a car to run rough?

Or is it the alternator or spark plugs or any other component that is restricting the power to not let your car run smoothly?

Well, these are some of the questions that arise in a vehicle owner’s mind sensing roughness and this is what you will learn about in this post.

What’s more, we will deep dive into the causes, symptoms, and remedies related to a weak battery. So, continue reading!

Can a weak battery cause a car to run rough?

Yes, it can. A weak battery can cause various issues in the car and rough idling is one of them.

One of the main reasons for a car to run rough meaning the engine is just not up to the mark while starting are spark plugs.

You will feel vibrations, loud noises, and in some cases even stalling/idling when spark plugs misfire for not getting enough electrical power from the battery.

A car running rough is not limited to misfiring spark plugs but it involves a hell lot of other reasons.

A battery is responsible to power all the electrical components of a car including the engine. This means if the battery itself is powerless all the other electrical parts are bound to take a hit.

Eventually, a car may run rough due to a bad alternator, and misfiring of the engine that affects many of its associated parts such as a fuel pump, pistons, valves, air filters, etc. to lose their effectiveness in starting or running the car properly.

If you feel your car is running rough or idle due to a weak battery look for the below symptoms.

Symptoms of a weak car battery

Here are some of the symptoms indicating a weak car battery that could be causing your car to run rough –

Difficulty starting the engine – If your car has a weak battery there will be difficulty in starting the engine.  As the battery is responsible for providing the initial power to start the engine any weakness in the power leads to pause, hesitation, and stalling of the engine in some cases.

When the battery is weak the ignition system of a car does not get sufficient power to pump the engine cylinders that move the car. Hence, the engine starts to misfire due to lack of power and if a car battery is totally dead the engine may not start at all.

Dull headlights and other electrical components – Another symptom of a weak car battery that is often visible upfront is the dullness or dimness of headlights.

Dimmed headlights of a car

If the dullness in headlights is difficult to observe you may also notice the interior lights of a car getting low. You can also see the performance impact on a car radio, GPS, dashboard, and any other component that relies on battery power.

This is because the battery that is responsible to power the electrical components is power sick. The sickness causes a significant drop in voltage levels of a battery and supplying the power to other parts of a vehicle gets difficult.

If you notice dimming of headlights and other electrical accessories it is a good idea to switch them off immediately to save some battery power.

Cranking or clicking engine sound – If the battery is weak a common sign that occurs while starting the engine is a click or a crank. This is very much audible when you enter the key and turn the ignition.

When you turn the key in the ignition, it prompts the starter motor to start the engine. However, due to a lack of power from the battery, it is just able to release a clicking sound while attempting to turn the engine on.

Clicking or cranking sounds should be enough to help you identify the weak signs of a battery and take appropriate action.

Warning lights on the dashboard – Many car dashboards flash warning lights when the battery is low on power. This is one of the easiest methods to realize the condition of your car battery.

The battery symbol is another common sign when you turn the key in the ignition however it remains on the dashboard for a long time even after starting the engine.

Dashboard warning lights

On some vehicles, there are warning lights other than a battery symbol indicating a problem in the car’s electrical system.  

Bad condition of the battery – You must also keep a tab on the battery condition once they have crossed their age. The ominous signs of aging begin with cracks and leakages on the battery case which makes it appear swollen or bloated.

If the battery has aged and started showing signs of cracks/leakages it won’t be able to hold the charge and voltage to power the electrical system and vehicle’s engine.

  • Once you have identified the symptoms of a weak battery it is important to get it repaired or replaced immediately for the smooth performance of your car.

Nevertheless, proper precaution and action are required to keep your car battery in good condition to avoid instances of weakness. To do this, it is imperative to know…

Causes of a weak car battery

So, what causes a car battery to get weaker? The causes may vary depending on the location, usage, and vehicle’s make/model but some of the common ones are listed below:

Age limit – If the battery has survived its lifespan which is normally between 3-5 years chances of weakness increase.

An aged battery lacks the ability to hold the charge for a longer time making it lose a significant amount of voltage rapidly.

Secondly, the combination of age and weakness deteriorates its condition from the inside and outside which results in cracks, damage, and leakage of fluids.

It is important to maintain your car battery properly for its longevity. In case it has crossed its recommended age ensure to replace it with a new one immediately.

Lack of maintenance – Lack of maintenance has many adverse effects on a car battery. A car battery expected to perform systematically should be monitored periodically.

If regular maintenance is not performed on a car battery it may catch corrosion and dirt on its terminals which will impact the current flow and also develop cracks and warps on the battery case resulting in the release of fluids.

Additionally, some of the battery components to look for are the water level, vent holes and plugs, terminals, etc. that will help you identify and repair the damages, or faults proactively.

Level of usage – The condition of a battery also depends on the way you use it. Using your vehicle excessively means putting continuous pressure on the battery.

Your daily ride may not be without touching the entertainment dashboard, charging your phone, using GPS, etc. which surely demands lots of power from the battery.

Car digital display screen

Some motorists do not bother to switch off the electrical components before turning off the engine which keeps your battery active. 

On the contrary, if the vehicle is hardly used or not driven frequently the battery may start losing its charge. If the usage is very limited a car battery doesn’t get sufficient opportunity to recharge itself with the help of an alternator making it weak.

To summarize, excessive or lack of usage of a car can play a crucial part in weakening your car battery.

Extreme temperatures – Weather has its own role in deciding the fate of a car battery. Extreme temperatures such as severe heat waves result in evaporating the battery juices which can damage its internal components.

On the other hand, too much cold is responsible to freeze the battery components making it weaker to start the engine.

Both types of temperatures can affect the performance of your car battery and in many cases, vehicle owners have to rely on charging solutions to activate a weak/dead battery.

Faulty charging system – When it comes to charging a weak or a dead battery a lot of us rely on battery chargers or jumper cables of low quality.

If the instruments used to charge or jump-start a car battery are not compatible or powerful enough to charge or withstand the current flow it may damage the battery.

A faulty charging system has the potential to weaken your car battery’s charge-holding capacity which can impact its performance.

Apart from the above, there are many more technical causes that can lead a car battery to become weak and even explode in some cases. Check the link to learn more about them.

Tips to prevent a car battery from weakening/dying

To prevent a car battery from weakening or even dying it is important to counter the causes of weakness with proper precautions and following below tips:

Proper maintenance – Timely maintenance is the best overall solution for any vehicle. It ensures thorough inspection, detection, and prevention of all the vehicle parts including the battery from any damage or shortcomings.

Ensure to test the condition of your car battery every 3-6 months with a voltmeter/multimeter. In addition, get the maintenance done on your car battery by a professional technician periodically for proper functioning.

Lastly, regularly inspect the battery terminals to detect any rusting and corrosion. Ensure proper cleaning method is applied to keep the terminals corrosion-free.

Balance the usage – Avoid making short trips on your vehicle. Such trips don’t allow enough time for a car battery to charge itself fully. In fact, short trips are instrumental in reducing the voltage power rather than gaining a charge.

Secondly, long periods of parking or non-usage may cause a car battery to drain its charge. In such instances, short-lived engine running will not suffice.

Ensure to take your vehicle for a minimum of 15-20 minutes drive that allows a battery to maximize its charge through the alternator.

Weather protection – Whenever you park the vehicle select a space that is shaded or remains protected from harsh weather conditions, especially heat. Heat causes a battery to weaken faster so make sure the car is sheltered under the shade.

Similarly, freezing winters are responsible to stall the functionality of a car battery. If you have a personal garage, it can come in handy to prevent the car battery from cold temperatures.

Turn off the vehicle completely – Before parking the car make sure to turn off the vehicle completely. This means not only the engine but all the electrical components as well.

Look for the connected accessories such as a Dashcam, charging cable, or any other device that works on electricity and disconnect them before leaving the vehicle.

Likewise, switch off the radio, headlights, interior lights, etc. to save battery power till the car remains parked or unused.

Can a weak battery cause transmission problems?

Absolutely, a weak battery causes many more problems than just running rough or stalling the engine. Transmission problems arise due to technical malfunctions in shifting and torque-converting engagements.

The transmission control module that works on taking power from the battery works erratically due to insufficient power supply and voltage fluctuations. This results in delayed shifting, slipping, and complete failure/damage to the transmission control module in some cases.

It is therefore important to keep the battery always in good condition to let other parts of a vehicle run smoothly.

Can a weak car battery cause computer problems?

Yes, a lack of power from the battery can cause a car’s computer or ECU (Engine Control Unit) to behave abnormally.

ECU is again powered by the battery to operate its functionalities such as gathering the data related to a vehicle’s electrical system, parts, and sensors.

When the weak battery drops its voltage level significantly the ECU may not be able to read and collect the data of a vehicle resulting in misleading information.

This may even impact the performance of your car’s electrical system such as a radio, AC, or dashboard gauges.

Steps to take when you find a weak car battery

When you get the symptoms of your car battery getting weak or not working up to its potential here are the steps to follow:

  • Take your vehicle to the side and turn off the engine
  • Before leaving the vehicle ensure to switch off all the electrical equipments and disconnect the accessories
  • Wear protective glasses and gloves to inspect the battery inside the hood
  • Now, open the hood and check the condition of the battery. Look for any loose connections or corrosion on terminals. If you can, clean the terminals and try to tighten the connection using appropriate tools (if available)
  • If the condition looks fine prepare to test the battery. You will need a voltmeter or a multimeter to perform the testing. Connect the equipments as per the guidelines to take the voltage readings.
  • A fully charged battery should read around 12.6 volts any reduction in readings means the battery is weak and needs recharging.
  • If the battery is weak make use of a battery charger or a jump starter cable for recharging. If the problem persists even after recharging it is recommended to replace the battery.

Here’s a small video showing how to test a car battery with a multi-meter:

Final thoughts

A weak battery is the root cause of various problems related to a vehicle’s electrical system and engine performance. A car running rough is one of them.

Illuminated dashboards, dimmed headlights, poor interior lightings, etc. are some of the symptoms of a weak battery.

Improper maintenance and usage of a car, challenging temperatures, aging, and human errors are the main causes of a car battery getting weaker.

It is important to regularly monitor and maintain the condition of a car battery in good health.

Proper precautions such as turning off the electrical accessories and components before switching off the engine, and protecting the car from hard weather can make the battery last longer. Replace the battery with a new one as soon as you feel it has aged.

Do not park your vehicle for too long and avoid making short trips frequently. These steps will ensure your car battery holds the charge longer and work uninterrupted to help you drive your vehicle peacefully.

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I am the founder of TheCarPlus. As a passionate car owner and enthusiast, I offer practical solutions and insights from my own personal experiences combined with extensive online research.

The purpose of creating this website is to empower fellow car owners and motorcyclists like 'YOU' with knowledge and practical solutions to enhance your vehicle's performance and aesthetics.

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