How to fix a dead car battery?

Don’t know where to find the answer to the question How to fix a dead car battery, have a look at our details to get information.

With the right tools in hand and clear instructions on how to proceed with this repair, hopefully you’ll be able to bring new life into your vehicle and get back on the road as soon as possible!


Common signs of a dead battery in a car:

  • A slow engine crank when attempting to start the car
  • Dim headlights or interior lights (or no lights) when the key is turned in the ignition
  • Weak or non-existent sound from the starter motor
  • No electrical power, such as odd behaviors from accessories like radio, windows, etc
  • Swelling, bloating or bulging of the battery case
  • Battery fluid leakage.
  • Sulfur smells coming from the engine bay
  • The battery posts or terminals are corroded or covered with white powdery residue




How to fix a dead car battery can be a tricky thing to figure out. One potential cause is age – when a car’s battery has been in use for 2-5 years, sulfation can occur.

This is when sulfate crystals coat the negative plates in the battery and build up, reducing its power delivery and preventing your car from starting. Whilst replacing the battery might seem like an expensive undertaking, it will help to ensure your vehicle runs as it should and could save you time and money in the long run.

2. Mistake made by the user

How to fix a dead car battery when it’s a simple user error? Most of the time, preventative steps are better than trying to fix the problem after it has already happened.

Accidentally leaving an overhead light on, leaving something charging in the accessory power source, or using too much accessory power when you’ve only driven a short distance can all be causes for a dead battery.

3. Poor Charging System

If your car’s battery warning icon illuminates while you’re driving, it’s possible that the issue isn’t related to the battery itself, but rather with a malfunction within your vehicle’s charging system.

Poor charging systems can cause a variety of issues and render the battery completely useless. To be sure of the problem, it is best to have a qualified mechanic assess your alternator, serpentine belt, battery cable and terminals, and alternator belt for proper function.


If you’re trying to fix your dead car battery, one of the first places to inspect is any potential corrosion on the battery terminals. Corrosion can occur over time from dirt or dust buildup, or acid leaking from the battery itself. It can be identified by white, ashy deposits between the posts and cables of your battery.

To remove this type of residue, use a wire brush and baking soda. If you need further assistance with how to fix a dead car battery due to corrosion, it is best to seek the help of a professional.



1. Jump-starting the battery:

Jump-starting a dead car battery is an important skill to learn and although it may seem intimidating, it’s actually quite simple. With just some jumper cables and another vehicle with a working battery, you can get your car up and running pretty quickly.

Be sure to start by turning off both cars, placing them in park or neutral and connecting the positive cable to the correct terminals. And don’t forget to ground the negative cable to a metal engine block – otherwise your car won’t start! After that, start the car with the working battery for a few minutes before attempting to start the car with the dead battery.

Running it for a few minutes after starting is also beneficial for charging your battery. With this full-proof methodology, you’ll be confidently jump-starting in no time!

2. Charging the battery:

Charging a dead car battery is an important task that can be done in two ways. The most convenient solution is to use a battery charger which you can connect to the battery and turn on and then wait until the charger indicates that the charging process is complete.

Alternatively, if you’re feeling more adventurous, you could start the car and drive it for at least 30 minutes – the alternator naturally charges the battery during this time. In either case, having a charged battery is essential for any car owner so make sure to find out what solution works best for your situation!

3. Cleaning the battery terminals:

Before you take loose the battery and run out to buy a new one, consider that corroded or dirty battery terminals are often the culprit.

To fix this problem yourself and save money, you’ll need baking soda, water, and a wire brush. Start by removing the cables from the terminals then mix baking soda into water until you create a paste.

Apply the paste with the wire brush to both the terminals and cable ends then scrub until they are clean. Rinse with water, then dry them off with a clean cloth to get your car back up running again!

4. Checking the alternator:

Are you dealing with a dead car battery even after trying to recharge it? Chances are, the problem may lie with the alternator not charging the battery.

To verify this and see if you need to replace the alternator, all you’ll need is a multimeter. Start by turning your car on and turning on the headlights.

Then set your multimeter to read voltage and check by touching the probes to your battery’s terminals. The normal reading should be between 13.5 and 14.5 volts; any lower readings means that your alternator needs to be replaced in order to fix your problem of how to fix a dead car battery!


Be proactive, not reactive

It’s far too common to find yourself in a situation where you need to know how to fix a dead car battery. No matter the situation, it’s always better to prevent damage than repair it. The best way to do this with your car battery is through regular maintenance and inspections.

Having an annual checkup can help keep your battery happy and healthy for many years so you will not have to worry about the potential for emergency repairs or having to buy a new one.

Investing a bit of time and money into properly maintaining your car battery will certainly pay off in the long run!


Can a Battery Be Too Dead to Jump?

Yes, if the alternator is not functioning properly and is unable to charge the battery, jumping will not help.

What are the signs of a failing battery?

Common signs of a failing car battery include difficulty starting your car, dim headlights/interior lights when turning on, corrosion around your terminals, or swollen sides on your battery.

Is it dangerous to jump start a car?

Incorrectly jump starting your car can cause serious damage to both cars by creating sparks or short circuits so it’s important to be familiar with the process beforehand.

Make sure you consult an expert if you’re unsure about any step in the process!

What is Battery Sulfation?

Sulfation is a chemical reaction that can occur in lead-acid batteries due to overcharging or leaving the battery unused for an extended period of time. This reaction causes a buildup of sulfate crystals on the battery’s plates, reducing its ability to hold a charge and eventually leading to failure.

Regular charging and maintenance can help prevent sulfation from occurring!

Can Battery Sulfation Be Reversed?

Yes, sulfation can be reversed with a process called desulfation. Desulfation involves charging the battery at a very high voltage to break down the sulfate crystals on the plates and restore their original condition.

However, it’s important to note that this process should only be done with professional equipment as incorrect voltages may cause damage to your battery.

How Long Can a Car Battery Be Dead and Still Be Recharged?

A car battery can still be recharged after being dead for up to two weeks. After this time frame, you may need to replace the battery as it may not hold a charge anymore.

If your battery is over 2 years old, it’s best to get a professional inspection or replace the battery altogether as age plays a big factor in how often batteries fail.

Should You Remove the Battery from a Car When Not in Use?

If you plan on storing your vehicle for a season, it is highly recommended that you remove the battery entirely. A good way to do this is to place the battery in a battery box and place it in a dry, well-ventilated area with an optimal temperature of 40℉ to 60℉.

Doing so will help preserve its life and prevent any issue like a dead car battery when you are ready to get back on the road. Additionally, make sure to check the charge of the battery every month, and charge it if it ever reaches below 70%.


A car battery should last between two and five years, but sometimes they die sooner. If your car battery dies, you can replace it with a new one or try jump starting it with another car. You can also take measures to prevent your battery from dying in the first place, like driving less and turning off electronics when your car is idling.

Hopefully this article helped you understand how to fix a dead car battery or how to keep your current battery healthy for as long as possible.

Do you have any tips for prolonging the life of a car battery?

Share them with us in the comments!

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