Like any part, the battery can break down, wear out, or run out of energy. And there is nothing more frustrating than the car not starting because of the battery, right?
Knowing how to change your car battery can get you out of a tough spot and save you time and money. But before you get started, it is essential to understand which one your car uses, look for affordable options to find a new one, such as buying a second-hand car battery, and what safety measures you should take.
Throughout this article we will guide you step by step through the entire process; from identifying the correct battery for your model, to all the tips for carrying out the replacement safely!
What is a car battery?
It is one of the most important components of the vehicle for its operation. In essence, it is an electrical energy storage device that provides the current needed to start the engine and power the car's electrical systems when the engine is off.
What are its key functions?
It mainly fulfils three functions:
- Starting the car engine, which is its main function.
- Powering the car's electrical components when the engine is off, for example, the radio, the hazard lights…
- It acts as a regulator, smoothing out voltage fluctuations in the car's electrical system to protect the electronic components.
How long does a car battery last?
The lifespan of a car battery varies and depends on several factors, such as:
Climate and temperature
Extreme climates, such as extreme heat or extreme cold, can damage batteries.
For example, heat accelerates the chemical reactions inside the battery, causing faster evaporation of the electrolyte and corrosion of the internal plates.
Cold, on the other hand, drastically reduces its ability to deliver energy. If it has been weakened by heat, it may fail to start on very cold days.
Driving habits
If you commonly use the car for short journeys of less than 30 minutes, the alternator does not have enough time to fully recharge the energy consumed by starting the engine, which leads to chronic discharge and reduces the battery's lifespan.
On the other hand, if you tend to leave the car sitting for a long time — for example, if you do not use it for a couple of weeks — this also affects the battery, as the electronic components continue to draw power and gradually drain it.
Using electrical components with the engine off
Stopping the car and leaving the radio on, charging your phone, leaving the lights on… Any electrical component or device that runs with the engine off will drain the battery.
Battery quality and type
Of course, the lifespan of a battery depends on its quality and the type your car has. Some last longer than others, as they are made with better components or are designed with more up-to-date technology so they do not consume as much energy.
Battery maintenance
It is true that most batteries today are maintenance-free, but it does not hurt to check them from time to time to make sure there are no signs of corrosion or a poor connection.
The signs that your car battery is about to run out
To answer the question: how often should you change your car battery? The norm is every 5–7 years.
These are some signs that it is about to run out:
- The starter motor turns slowly and struggles to start.
- The dashboard lights flicker or dim when starting.
- The headlights shine with less intensity than usual.
- The battery warning light comes on in the dashboard.
- A repetitive clicking sound is heard when trying to start.
- Appearance of whitish or bluish corrosion on the terminals.
- The battery casing appears swollen or deformed.
- Near the battery there is a smell of sulphur or rotten eggs.
How to change a car battery? These are the steps!
You do not actually need to go to a garage to change your car battery. It is a process you can do yourself, and at Recoautos we are going to explain the steps to follow.
How do I know which battery my car uses?
First of all, you need to know which battery your car uses. Whether you are going to buy it second-hand or new, it must be the right one.
These are the details you should consider:
1. The voltage. Almost all modern cars use 12-volt (12V) batteries.
2. Check the Ampere-hours (Ah) of your battery. This information is printed on a label on the top or side of the battery. Important: you cannot replace it with a battery with a significantly lower Ah than the one recommended by the manufacturer!
3. Cold Cranking Amps. Represented by CCA, this refers to the battery's ability to deliver a high current in cold climates. The value of the new battery must be equal to or higher than the original.
4. You need to measure the length, width, and height of the battery, to make sure the replacement fits perfectly in the compartment.
5. You must also check the position of the positive and negative terminals, which are generally marked with a red colour for the positive one. Each battery has its own terminal layout, and it is essential that the new one has the same layout so that the car's cables reach correctly.
6. Finally, it must be the same type as the one in your vehicle. You cannot fit a Lithium one, for example, if your car has a Lead-acid battery.
What tools will you need?
Now let's look at the tools you will need to carry out the replacement:
- Tube or open-end wrench.
- Metal bristle brush or terminal scraper.
- Safety gloves.
- Safety glasses.
- Rags or absorbent paper.
- Water with baking soda.
- Terminal grease.
- Compatible replacement battery.
Steps to change the car battery
Let's get started with the procedure to replace the old battery in your car with a new one! Pay attention!
Preparation and safety
First of all, some prior preparation is needed:
- Park the car on a flat, safe surface. If possible, in a well-ventilated area.
- Turn off the engine and remove the key, making sure all electrical systems are switched off.
- Open the bonnet and locate the battery.
- Put on your safety glasses and gloves.
- Inspect the current battery to see how the terminals are connected. To avoid any mistakes, take a photo.
Disconnecting the old battery
We move on to the process of disconnecting the old battery:
1. The first step is to disconnect the negative terminal (-), using the appropriate wrench to loosen the nut on the negative terminal.
2. Remove the cable from the terminal and secure it so that it does not touch any metal part of the car or the positive terminal (you can cover it with a rag or a glove).
3. Next, loosen the nut on the positive terminal. As with the negative one, make sure you move it aside and secure it.
4. Remove the securing system, usually a clamp, strap, or a bolt at the base.
5. Remove the old battery. And if you have ever wondered how much a battery weighs, its weight ranges between 13–23 kg. So be careful when carrying it and, above all, do not tilt it, in case of acid leaks.
Cleaning and inspection
We proceed to clean the battery compartment, removing any dirt, rust, or residue.
Are there traces of corrosion? In that case you can use a mixture of water and baking soda to neutralise it, along with a brush to clean. Rinse with clean water and dry.
You should also use the terminal brush to make sure the cable connectors are clean and free of corrosion.
Battery installation
Now we need to fit the new battery, following the steps we took to remove it in reverse:
- Place the battery, very carefully, in the compartment, making sure the terminals are in the same orientation as those of the old battery.
- Secure the battery by fitting and tightening the securing system so that it is anchored and does not move.
- Connect the cable to the positive terminal first. Tightening it firmly with the wrench.
- Connect the cable to the negative terminal, again making sure it is firmly tightened.
- Apply terminal grease to prevent future corrosion.
Final test
Finally, there is just one thing left to do: the last checks.
After closing the bonnet, start the car to check that it starts without any problems and that all electrical systems are working. You may need to reconfigure some of them, such as the clock, the radio, or the window memory settings.
What should you do with the old battery?
It may sound logical, but… You should not throw it in a bin! Once you have installed the new battery in your car, here is what you need to do with the old one:
Hand it in to the garage or shop where you bought the other one
The first option, and usually the most common and straightforward, is to hand it in to the garage where you bought the other one. By law, these points of sale are required to collect old batteries free of charge for recycling.
Take it to the Clean Point
The other option is to take it to an Ecopark or Special Waste Collection Centre, which have containers for storage and subsequent recycling.
Contact a waste management company
If you cannot take it to the Clean Point or the garage where you bought it, there are companies specialising in the recycling of metals and hazardous waste that buy and collect used batteries.
Hand it in to the scrapyard
Scrapyards, or Authorised Treatment Centres (ATC), are also authorised to collect and manage car batteries.
Where can you buy a car battery at the best price?
The price of a battery can vary greatly depending on the type of material, the amperage, the voltage…
So you have two options:
- The most affordable option is to buy a second-hand car battery. Scrapyards usually sell them at very good prices and they are in perfect condition to last between 3–5 years. Moreover, if your car is a bit older, you will increase your chances of finding one compatible with your vehicle.
- Buy a new one at a garage or a specialist vehicle shop. This is the most expensive option.