How to fix a car battery - 4 easy methods

A car battery is the part of the car that enables it to start up as soon as you turn the key in the ignition. As important as this part of the vehicle is, it is expensive to replace once it stops working. This article will enlighten you on 4 ways to fix a car battery so you can get more out of the battery.

The following processes can help fix a car battery

  • Topping off the distilled water and acid levels
  • Jumpstarting the battery
  • Using Epsom salt
  • Aspirin

In a moment, we will dive into the explanation for the various ways to fix a car battery. Before that, let us understand how a car battery works and how it dies.

How to fix a car battery

Structure of a car battery

Structure of car battery

To better understand the mechanism behind the process of fixing a car battery, let's look at the battery's components. A standard car battery is made up of the following components

  • Battery Acid
  • Battery Terminal
  • Cast-on Strap for Batteries
  • Battery Separator
  • Lid on Battery
  • Battery Positive Plate
  • Negative Battery Plate
  • Battery Paste
  • Casing for the battery

Battery acid

Sulfuric acid (H2SO4) and distilled water form the highly purified solution known as battery acid. The solution is usually 30% - 50% sulfuric acid in water and always around a concentration of 4.2 – 5 mol/L.

Battery terminal

These are the two points on the battery that interacts with the vehicle's electrical system. Battery terminals are connected to the positive and negative straps of the end cells. They are metal clamping devices with high conductivity because of their function.

Also, types of terminals are based on battery polarity, forms of the compound, installation diagrams, and manufacture material.

Cast-on straps for batteries

These exist to allow electrical connection to both terminals. You will find the cast-on straps welded on the top of the terminals.

Battery separator

This part of the battery separates the positive and negative plates from each other. It is made of polyethylene material.

Lid on battery

Made of polypropylene resin, the lid on the battery is sealed on the battery case as a cover.

Battery positive plate

A lead oxide (PbO2) active material is used to make the metal grid that acts as the battery's positive plate.

Battery negative plate

The metal grid that functions as the battery's negative plate is made of spongy lead (Pb) active material.

Battery Paste

This is a lead oxide mixture that sticks to the positive and negative plates. It creates both sponge lead and lead oxide.

Casing for the battery

The battery case acts as the container for every other part of the battery. Manufactured using polypropylene resin, it houses the battery plates, the electrolyte (battery acid), and minimizes vibration impact.

How a battery works

A battery generates electricity through the flow of electrons from the anode to the cathode. The negative battery plate functions as the anode, while the positive battery plate acts as the cathode. Both are suspended in an electrolyte solution, which in this case is the battery acid.

In addition to the above, positive and negative plates are separated by a semi-permeable barrier called the battery separator. The current generated by the battery is, in turn, used to start the car engine.

How a battery dies

Dead car battery

An average car battery's lifespan sits at around 4 – 7 years. The latter being the case with a well-maintained and optimally utilized battery. Despite this, there are a couple of things that reduce the life of a car battery. While most of them can be prevented, other things cannot be avoided. When a car battery is used, electrons flow from the negative plate to the positive plate, and both vessels gradually become chemically similar.

Charging the battery reverses this process, resulting in soft battery sulfation. Leaving the battery in a discharged state for long periods will result in hard sulfation, which leads to the formation of sulfate crystals. These crystals gradually reduce the surface area available for the chemical reaction that generates currents. Because of this occurrence, the ability of the battery to charge and discharge becomes diminished.

Sooner or later, the sulfate crystals will spread to a point where they lead to short circuits and cracks inside the battery. When a car battery dies, it becomes unable to hold a charge and ultimately cannot start a car any longer.

Reversing hard sulfation is impossible regardless of any product or manufacturer claiming to achieve this feat. Nevertheless, there are a couple of things that you can do to get back on the road.

However, once you start your vehicle using any of these methods, please do not turn it off until you have a new car battery. The reason is that the options provided below will end the battery's life.

How to fix a car battery

Topping off distilled water and acid levels

battery acid

This method involves adding distilled water to the acidic solution inside the battery case. Your first step should be measuring the faulty battery, topping it off with distilled water. The added liquid serves to activate the acid so the battery can yield more voltage. While this method will allow the battery to start the engine a few more times, it works best if the battery solution was noticeably reduced.

Because the addition of distilled water raises the volume of the battery solution, it creates a larger surface area for reactions to occur. If the acid spilled before battery inefficiency, add the right volume of missing sulfuric acid. However, if it's a simple addition of distilled water, make sure to charge the battery after. The charging process will begin the required chemical reaction.

You see this method as one of the effective ways to fix a car battery

Jumpstarting the car battery

Jumpstarting the car battery works best for emergencies as your battery will not be receiving any charge. However, never try to jumpstart a frozen battery; it will most likely explode. After successfully jumpstarting the battery, do not turn your engine off until you replace your battery.

To carry out the process of jumpstarting, you will need a second battery, jumper cables, battery booster, or make use of a second vehicle. The process starts with putting both vehicles in Neutral or Park, then shut off both cars' ignition.

After this, bring out your jumpstart cables and attach the red clip to the positive terminal (+/POS) of your battery while the other red clip goes to the other car's positive terminal. Pick one of the black clips to attach to the other car battery's negative (-/NEG) terminal.

Once done, find an unpainted metal surface anywhere on your not close to the battery and attach the last black clip there. Now, start the right vehicle and its engine run for a couple of minutes, then attempt to start your car. If it works, do not turn off your engine. Driving around for about 20 minutes should try to charge your battery.

If the battery fails to start your car next time, you have to replace it.

Using Epsom salt

Epsom Salt

Adding Epsom salt, also known as magnesium sulfate, to the electrolyte mix can make it reactive enough to generate the required charge for starting your engine. You will find Epsom salt (MgSO4) in drug stores, home gardening centers, and even grocery stores.

To use Epsom salt, dissolve 1-part magnesium sulfate in 3 parts warm water, now add the solution to individual cells till all plates are immersed in 0.25 to 0.5 electrolyte. You should note that after using the Epsom salt to start your car, you should get a replacement as the battery will only give the last effort and then die. Find out other uses of Epsom salt here.

Making use of Aspirin


In a case where you've got no Epsom salt close at hand, Aspirin can do the trick. Also known as Acetylsalicylic acid, dissolving it in water and adding it to the battery solution will allow the battery to squeeze out the needed voltage. Get about 12 Aspirin tablets (325mg or 500mg), crush them, and dissolve around 6oz of warm water. Add equal amounts of the solution to the battery's cell, then add extra water to ensure that the plates are well covered.

However, the warning remains the same as when using Epsom salt; get a replacement after. The battery will only give your vehicle one last start. This method works in emergencies, don't use it as a first choice to fix a car battery.

The only effective remedy to a dead battery is to prevent it in the first place. Below, you will find the ideal practices to help your car battery live longer and perform better.

Essential maintenance practices for car batteries

The following steps are based on helping you maintain your car or truck battery.

  • Check your battery regularly to ensure that both terminal connections are firm, clean, and well shielded from the elements. If you spot any sign of leakage or corrosion, it's a sign that the battery is becoming weak.
  • You should also find out how much your battery weigh. It influences the battery's functioning.
  • Always keep your battery in cool places whenever possible as heat damages batteries in general.
  • Whenever you turn your car off, make sure to disconnect vehicle accessories and switch off the lights. Speaking of car accessories, check out this article on the best Bluetooth car adapters.
  • Make sure to scrub corrosion from the terminals as soon as you spot them. It would help if you did this using a solution of baking soda and water.
  • To minimize the vibrations getting to the battery while the car is moving, secure the hold-down bar.
  • Regularly test the battery to ensure it is charged correctly. If it's not, you should charge it to help it maintain its optimal performance.

When your battery is in storage, say for an extended period, the best way to prevent chemical damage is to check its voltage regularly. You should make sure that its voltage does not drop below 12.4 volts. You can achieve this by using a maintenance charger. In cases where you do not have access to a maintenance charger, do well to disconnect the battery from the vehicle by separating the terminals.

This action prevents the car from discharging the battery. To better protect your car battery, you can make a battery box to house it. Check this article I have written on how to build a battery box.

How to disconnect a car battery

how to disconnect a car battery

To safely disconnect your car battery, ensure to take these safety steps.

  • Ensure that you are not wearing any jewelry like a wristwatch, ring, or bracelet. The reason is that batteries store electrical charges and is likely to give you a little shock if handled poorly.
  • Always check to ensure that the area in which you are working is arid and free of moisture. Detest from working in humid environments or surroundings with humidity.
  • Anytime you want to work on your car battery, always do it in the open. Batteries might release harmful gasses now and then, so being exposed to the open air means you don't inhale the gasses.

Disconnecting the battery

Now, to disconnect your car battery, follow the steps highlighted below.

  • Turn off the car's ignition and also use the safety apparatus. This means that you put the vehicle in 'Park' if it is automatic or the first gear if the car came with a manual transmission. Leave the driver's door open and put on safety goggles and gloves if you have some; to prevent inhalation of harmful gasses.
  • Open the car hood. You do this by pressing the button located around the section below and near the steering wheel. However, some vehicles have a hood lever instead of a button. You will find it in the same area.
  • Locate your car battery. After opening the car hood, you will find the battery towards the front of the car. Do not forget to keep the hood in the right place using the rod.
  • The first terminal to disconnect is the negative terminal of the battery. You will need a wrench first to loosen the nut holding the terminal. After the nut is loosed, use your hand (covered with safety gloves) to remove the nut and keep it in a safe place. Then remove the cable attached to disconnect completely.

Disconnecting the negative terminal first helps to reduce the risk of sparks that can make a battery explode.

  • Disconnect the positive terminal of the car battery in the same way as the negative terminal.
  • Locate the battery bracket and proceed to remove it.
  • To install the battery back, carry out the process in reverse to the way you disconnected it.

Key Takeaways!

This section covers the main points for readers who are unable to read through the whole article.

  • A car battery can last up to 7 years with the right maintenance practices
  • Each time the battery is used, both plates begin to become chemically alike to achieve equilibrium.
  • After a battery dies, it can still be coaxed into giving a few more starts.
  • To fix a car battery, you can jumpstart the battery, use Epsom salt, top its distilled water and acid levels, or use aspirin.
  • Any of the methods above are not permanent solutions. You should get a replacement as soon as possible.
  • After getting the car to start up, please do not turn it off until you replace the damaged battery as it will not work again.
  • Acceptable maintenance practices are the best way to prevent bad batteries.
  • Always disconnect your battery the right way, following the steps provided in the 'how to disconnect a car battery' section.

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