A car battery consists of several cells, each with a common function; regulating the voltage in the battery.
The cells inside the battery have the most impact on its functionality and performance. There are times when one of the cells in the battery gets bad.
This dead cell in car battery or a bad battery cell can affect the efficiency of the car battery and significantly impede the amount of operating power circulating in the vehicle.
Typically, a dead battery cell has a lower voltage than the other cells within the same battery.
Car batteries have a general lifespan of about four years. As soon as one cell in the battery becomes faulty, it decreases the power and effectiveness of the battery when you need to start your car.
In certain circumstances, this can get really frustrating, especially in cold weather where starting your vehicle could turn out to be extremely difficult.

For many drivers, having a dead cell in a car battery is a major pain to deal with.
You could easily get stuck and be left stranded because of a dead cell(s) in your car battery. As a result, it’s important to understand what causes battery cells to die.
This article will help you avoid those needless deaths. Let us first look at the signs of a bad car battery cell. Later on, we’ll look at how to fix a bad cell in a car battery.
Signs Of A Bad Car Battery Cell
Most automobile batteries are designed to produce 12V. This implies that there are six cells within the battery, each of which can generate 2 volts.
Each cell also contains an electrolyte of sulfuric acid and water, as in the case of lead-acid battery types. Therefore, when there’s one dead cell in a car battery, you will notice changes in your battery’s performance.

The following points are tell-tail signs of a bad car battery cell:
1- Slow-cranking Engine
This is one of the major signs of a bad car battery cell. If your engine takes too long to start, it could be because there are one or more dead cells in your car battery.
A dead cell in the car battery prevents it from delivering the required amount of direct current voltage to the car engine. As a result, the motor is unable to draw the correct number of amps during the ignition. In a nutshell, a bad cell significantly lowers the amps, causing difficulties in starting your car.

2- Car Lights Dimming
Most car batteries have six cells. A weak cell would mean the difference in voltage and power between some cells and others, leading to dim lights.

This would occur when two cells in the car battery work together to make up for the third cell, which is dysfunctional.
The voltage, in this case, causes the diming car taillights
3- Dash Lights Work, But The Car Won’t Start
On some occasions, your dash lights may function when the headlight switch is turned on, but you push the ignition and the car refuses to start.
This, too, can be a typical indicator of a bad battery cell.
The battery’s internal wiring carries power from one terminal to another. So when there is a dead cell in the battery, it would affect how well or badly the cells work together as far as the wiring is concerned.
3- Car Battery Wiring Is Damaged
Most car battery casings are made from plastic or lead. This means that there are pieces of metal touching pieces of other metal, which provides a path for electricity to flow.
A car’s system needs a minimal amount of voltage to function properly.
As a result, an overworked, damaged car battery cell could cause current to flow through the path of least resistance, which might be the battery’s casing. If this is the case, it will cause overheating or short-circuiting in that area of the battery.
4- Car Battery Case Is Cracked
If you notice that your car battery has a cracked case, then it’s more than likely, that there’s a dead cell within.
Such cracks are usually the result of overheating, which may be caused by a bad cell in your car battery.

5- Car Battery Corrosion
Usually, dead cells are accompanied by rust on the terminals and cable clamps.
The corrosion happens when the water inside the cell evaporates, leaving the metal exposed. This occurs as a result of vacuum or pressure inside the cell.
How To Repair A Dead Cell In Car Battery
If your car’s electrical system has already shut down, then there are specific tools that can help you locate the bad cells in your car battery.
- You could use your car’s multimeter (if you know how to use it) in order to get this done. These meters will measure the voltage of each cell and tell you if there is a bad one or not.
- You can also compare the voltage readings on all cells with known good batteries, such as your old battery or a spare/replacement battery if you still have one.

Reconditioning A Dead Cell In Car Battery
Reconditioning batteries is one of the most reliable methods to extend their lifespan and save money on car maintenance. Car battery reconditioning may be done at home, in a well-ventilated space using the following basic equipment and easy procedures.
- Drill
- Goggles
- Neoprene Rubber Gloves
- Plastic Funnel
- Screw Driver
- Epsom Salt
- Distilled water (half a gallon)
- Battery Charger
- Turkey Blaster
Reconditioning Procedure
- Boil right around 1/2 quart of de-ionized water to about 150 degrees Fahrenheit.
-Fill a large mixing bowl with 8 oz (1/2 lb) Epsom Salt (magnesium sulfate) and add it to the heated water.
-Stir it up together and continue mixing until all of the salt has dissolved. - To prevent contamination, clean the outside of the battery with baking soda and water.
-Make sure there is no corrosion on the cable connections and battery terminals. - Remove the covers from the battery cells with a screwdriver carefully.
-Remove the top cover of the sealed battery first, followed by the plastic covers,, and drill holes into the impressions.
-Using a wet cloth, clean away any debris around the battery openings. - Remember not to use a metal funnel to fill the batteries with the acid-neutralizing solution since this will react with the chemicals.
-Fill the batteries with the prepared solution.
-When the battery covers are completely immersed, replace them. - Connect the battery terminals to the battery charger and charge for 24 hours at a moderate speed. This process can be repeated up to three times in a row to extend the battery’s life.
You may now be able to resurrect your battery using the methods outlined above. This can help you save money and resources by not having to invest in a new battery.
On a concluding note, a dead cell in a car battery may be due to several reasons, some of which can be fixed, pretty easily.
However, if you notice that your battery has a broken case or some other exterior damage, then you should consider getting it replaced as soon as possible or take the less expensive route and use Tom’s expert battery reconditioning guide to bring your dead battery back to life.
The tips and techniques you will learn from Tom will give you a step by step system for breathing new life into your old/dead battery, so you never have to spend money on new batteries ever again, nor will you ever have to be stuck or frustrated on the middle of nowhere because of a dead battery!