Car Battery Problems? 12 Most-Common Issues & Fixes

Car batteries should only last a few years. If yours has been acting up lately, it may be ready for replacement.

Before you decide to spend money on a new one, here are the 12 most common issues you should check with your current battery and how to fix each item.

This article is not about electric vehicle (EV) batteries. Check this article about problems with electric car batteries if you’re looking for that. Also, here’s an easy guide to understanding the basics of car batteries.

How to Identify Problems

Tools You’ll Need to Identify & Fix Common Battery Problems:

  • Voltmeter
  • Wire Brush
  • Sandpaper or Battery Terminal Cleaner
  • Anti-Corrosion Felt Washers or Di-Electric Grease

Measure Your Current Battery Voltage Before Identifying Problems

Before you put on your Sherlock Holmes hat and start on the trail identifying problems, you should check the current voltage of your battery.

The exact voltage of the battery can’t identify the problem, but it will give some indication if the battery can hold a charge.

  • A fully charged battery should have a voltage greater or equal to 12.6 volts.
  • A dead or dying battery will have a voltage of 12.0 or less.
  • Your battery should show a voltage between 13.6 and 14.6 volts when the vehicle is running, indicating your Alternator is performing correctly.

This table indicates the approximate charge level based on the voltage in the battery.

Charge Level (%) Battery Voltage (V)
100% ≥ 12.6 volts
75% 12.5 volts
50% 12.3 volts
25% 12.1 volts
0% ≤ 12.0 volts


#1 – The Most Common Problem is a Dead Battery

The most common problem with vehicle batteries is they are dead or empty of charge. You’ll usually find this out by trying to start the vehicle and it doesn’t do anything.

The culprit may be that:

  • The vehicle sat for a long period of time, which drained the battery
  • The alternator is bad and drained the battery
  • The battery is old
  • The battery could have corrosion on the terminals

How to Fix It:

Your first solution should be to charge the battery to know if will hold a charge. Once it’s charged, you can use the table above to know if it will hold a full or only a partial charge.

If you’re in a hurry, you can try to jump-start the vehicle using another vehicle and battery jumping cables. That may start your vehicle, and you can then test the charging voltage to understand if your Alternator is performing correctly, too.

#2 – You Forgot to Turn Off Your Headlights

This issue gets everyone at least once unless you have automatic headlights that never leave the headlights on.

Headlights draw a lot of power from the battery if the vehicle isn’t running. A car battery can be fully drained in as little as 4 hours.

How to Fix It

If your headlights are left on without the vehicle running, you need to turn them off as soon as you discover them on.

If they have been on for more than 15 minutes, you should start your vehicle and allow it to run for a few minutes at idle to recharge your battery. This will help with starting the vehicle next time.

If the battery doesn’t start the vehicle, you need to have it charged with a battery charger or jump-started with another vehicle and allowed to run to charge your battery.

A trailer may also slowly drain your car battery.

#3 – You Have Loose Battery Terminals

Loose battery terminals are pretty common, especially with top-mounted terminals. Most mechanics will recommend that you check your terminal connections at least twice a year or at every oil change.

If you find they are loose to the touch with your hand or have any corrosion, it’s time to spend a few minutes remedying this problem.

How to Fix It

Loose terminals need to be tightened again, assuming the terminals are clean without grease, dirt, or corrosion.

If they are dirty, you can remove the cables from the battery (remove the negative cable first) and gently clean them with a degreaser. If they have corrosion, you can clean them with a terminal cleaner.

Once they have been cleaned, you can reinstall them and tighten them accordingly with a socket and ratchet or a wrench.

Make sure to install the positive cable first, and then the negative cable second.

#4 – Your Battery Is Very Old

Car batteries are rated to last between 3 and 5 years on average.

If you drive your vehicle in extreme conditions such as freezing cold, high heat, or salty conditions, it may last toward the minimum of the range.

Aging batteries will show signs of losing the ability to hold a full charge.

How to Fix It

Unfortunately there isn’t an easy way to turn back the clock on your battery. If you find your battery is starting to lose the ability to hold a full charge, it is time to look at replacing it.

If all this has you scratching your head, check out our article explaining the A to Z of car batteries. 

#5 – Your Car Has A Charging Problem

Your alternator is designed to produce power when the engine is running.

The alternator should produce a voltage between 13.7 and 14.7 volts that will charge your battery to full capacity.

If it has failed, your car may illuminate a light in the gauges because the battery is not being charged correctly.

You can drive your vehicle temporarily without a working alternator because the battery will provide the power needed to run the car. The longer you drive, the lower your battery voltage will become, and eventually, it will run out of power.

How to Fix It

You can test if your alternator is working correctly by verifying the voltage at the battery terminals while the engine is running.

If it shows between 13.7 and 14.7 volts, the Alternator is working correctly. If not, the alternator should be replaced.

#6 – Your Battery Terminals Are Corroded

Your battery terminals can develop corrosion due to a chemical reaction. Corrosion will be a white or light green/blue chalky substance on the terminals and cables.

This can occur due to overcharging of the battery, an acid leak from the battery housing, or a battery that is beyond its service life.

How to Fix It

  1. If you find corrosion on the terminals or cables, first neutralize the corrosion with a baking soda and water solution.
  2. Apply the solution to the corrosion and let it sit for 5 minutes before moving forward.
  3. Once the corrosion is safe to handle, you can then use a terminal cleaner to remove the corrosion and reinstall the terminals correctly.

To reduce corrosion in the future, place an anti-corrosion felt washer on the battery terminal before installing the battery cable. This will add protection from the chemical reaction.

You can use di-electric grease on the battery terminals as an alternate solution, too.

#7 – Your Battery Is Low On Water

Lead-acid batteries contain an acidic fluid that has electrolytes suspended in the fluid. If the liquid level inside becomes too low, the electrolytes can’t hold voltage.

Before adding water to your battery, check that it is a serviceable type of battery. Some are sealed from the factory, and they have no way to add fluid if it becomes too low.

How to Fix It

  1. Assuming you have a battery that can be serviced, you can remove the caps on top of the battery.
  2. You can add deionized or distilled water into each reservoir (also called cells) until the water reaches the bottom of the opening.
  3. Do not fill the reservoir any higher than that as it will need room to expand.
  4. Check your battery water level at least once per month and add distilled or deionized water as needed.

Note: Always use protective equipment such as safety glasses and gloves when handling the battery.

#8 Extreme Temperatures Will Damage Your Battery

Knowing that your battery may contain an electrolyte fluid based in water, extreme temperatures can affect how the battery performs.

Freezing temperatures can drain your battery 30% to 60% faster and inhibit it from fully charging. Extremely hot temperatures can also reduce the battery performance.

How to Fix It

You can’t change the weather conditions, but you can change the temperatures around your battery.

If you live in a climate that sees freezing weather, park your vehicle in an insulated area that reduces the chance it will contact freezing conditions.

If you live in extremely high temperatures, park your vehicle in a cooler spot in the shade or in a building out of the sun.

#9 – Your Battery Case is Swollen And Bulging

Batteries are currently housed in a plastic casing that can become swollen and bulging if the battery has been overcharged or damaged due to extreme vibration and heat.

This condition indicates there is a problem, and the battery shouldn’t be used anymore.

How to Fix It

Once the battery is damaged to the point of bulging or becoming swollen, there isn’t much you can do to fix it.

If it has an internal cell problem, you should replace the battery.

You can use a voltmeter to determine if your alternator is overcharging the battery (the voltage should not be higher than 14.7 volts with the engine running). If the alternator produces too high of a voltage, it may also need to be replaced with the battery.

#10 – Your Car Battery Is Leaking Fluid

Your battery can show signs of sweating or leaking fluid if it:

  • is being overcharged
  • has too much fluid in the reservoirs
  • just appears wet.

You may also smell rotten eggs around the battery from sulfuric acid leaking from the reservoir caps if they are not installed correctly.

How to Fix It

  1. Use a water and baking soda solution to neutralize any acid you see on the battery casing.
  2. Once the acid has been neutralized, you can use vinegar to clean the area and then determine why the battery is leaking.
  3. If the battery casing is cracked, replace the battery.
  4. If the reservoirs are overfilled, you can remove a small portion of the fluid. Just remember to wear protective equipment as the solution is acidic.
  5. If the caps are not installed correctly, put them on correctly to prevent fluid from escaping.

#11 – Your Battery Has Damaged Cells

Most 12-volt car batteries have 6 cells that each hold approximately 2 volts. You may find that your battery won’t hold a full charge because one or more of the cells have been damaged.

How to Fix It

There is no way to repair an individual cell inside most car batteries. You will need to replace the battery.

#12 – You Have Poor Driving Habits

Sometimes the biggest problem with your car’s battery is YOU.

Frequently starting your vehicle without allowing it to run long enough to recharge the battery will consistently drain the battery.

If you are running too many accessories like a large stereo system or extra lighting, it can also drain the battery.

How to Fix It

If you start your car frequently, allow it to run for a few minutes to fully recharge the battery before turning it off.

If you run a large amount of accessories, it may be a good option to install a larger alternator that will produce more power or add a second battery for additional power in the electrical system.

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