Ultimate guide to changing your car battery

If your car battery has reached the end of its life and needs to be replaced, you have several options:

- Firstly, you can take your car to a garage to have the battery replaced. For example, you could have your car battery replaced at Norauto, Aurgi or your local garage. However, this requires making an appointment at the garage, starting the car somehow, taking it to the garage, waiting for the battery to be changed, and returning again to pick up the car when it is ready. Apart from all this time, of course, the garage will make a profit on the battery and the replacement. This option is therefore more expensive and more cumbersome.

- Another option could be to buy the battery from a parts shop or a shopping centre that sells batteries, such as Carrefour or Alcampo, and install it yourself. However, these shops are not usually battery specialists, they are likely to give you batteries that have been in storage for some time, and they will not give advice on the most suitable battery for your vehicle.

- And finally, you have the option of buying your battery on our website, where we will advise you on the most suitable battery for your vehicle, where you can buy your top brand battery at the best price on the market and where, in addition, we will advise you on the installation of your battery.

In this article, we will also explain how to change the battery of your car without having great knowledge of mechanics. We are going to give you some tips to change your battery safely, we are going to tell you the most common tools required to change the battery and we are going to give you maintenance tips so that your battery lasts as long as possible.

At the end of our article you will see that changing a car battery is easy if you follow our short tutorial.

Idea: changing your car battery is easy if you follow our instructions.

Tutorial on how to change your car battery

If you follow the steps in this tutorial you will be able to change your car battery yourself, saving time and money and with the personal satisfaction of having been able to carry out a task that most people, due to lack of knowledge, think is complicated.

Before changing your battery, we advise you to have the following tools at hand:

- A spanner to disconnect the terminals or poles. The most common is a 10 mm wrench.

- If the battery has a bottom connection, a socket spanner. You will usually need a number 13 socket spanner.

- A hammer to secure the vehicle connector to the terminal.

In the old days, before changing and in order not to de-program the radio or other car components, it was common to power the vehicle with another battery, either through the cigarette lighter connector or by connecting another battery to the vehicle's connectors. This, in addition, brought more problems than solutions: we ran the risk of blowing the car's fuses, the battery was disconnected when changing the battery, etc... Nowadays it is not usually necessary, as most cars can withstand the battery change without problems and the most that is not trusted is the time and the radio stations that we have programmed.

Therefore, in general, its use is not recommended, unless it is a very old car and we do not have the radio code.

Step 1: Accessing your car battery

In the vast majority of cars, the battery is located under the bonnet, however, in other vehicles, such as some Mercedes and BMWs, it is located in the boot or under a seat.

Therefore, the first step would be to access your car's battery.

Step 2: Remove the battery from the vehicle

To remove the battery from the vehicle, you will first need to disconnect the battery from the car. To do this, it is very important that you disconnect the negative terminal of the vehicle first. There is, therefore, an order to follow when disconnecting the battery.

But why do we have to disconnect the negative terminal first?

Quite simply: the entire exterior of the vehicle is connected to ground (battery negative). If we try to disconnect the positive terminal first and inadvertently touch any part of the vehicle with the tool, it is very likely that we will short the vehicle (we are connecting the positive of the battery to the negative).

However, if we disconnect the negative side of the battery first, if we touch any part of the vehicle without realising it, we would be connecting negative to negative (or ground to ground), which would have no effect and, moreover, when we finish disconnecting the negative pole and go to disconnect the positive pole, even if we touch any part of the vehicle as it is already disconnected from the negative side, it would have no effect either.

For this reason, we must first disconnect the negative pole of the battery and then the positive pole.

Once we have disconnected the battery from the vehicle, we would remove the battery's grip on the vehicle. To do this we would use the socket spanner if necessary.

Once the battery is loose, remove it carefully so as not to damage or rub any of the vehicle's components.

Important: Before doing anything else, disconnect the negative terminal of the battery.

Step 3: Connecting the new battery to the vehicle

Once we have the battery out of the vehicle, we first proceed to insert the new battery into the vehicle. It is very important that you connect it in the same position as the old one and that you make sure that the negative terminal of the battery coincides with the negative terminal of the vehicle. And therefore the positive terminal of the battery would also match the positive connector of the car.

Once the battery is in place and we have checked that the battery terminals match the terminals of the car, we proceed in the opposite way: first, we install the battery grip to the vehicle, we first connect the positive terminal to the vehicle (for the same reasons as explained in the previous point) and, finally, we connect the negative terminal.

Important: Make sure that the battery terminals match in polarity with the vehicle terminals.

Step 4: Testing the battery

Once we have the new battery installed, we proceed to check that it starts without any problem and to configure the elements that may have been deconfigured: time, radio stations, etc...

In some modern vehicles, it will be necessary to drive the vehicle for a while so that the car detects that the battery has been changed and the error messages are erased. On other vehicles, it may also be necessary to configure the control unit to tell the vehicle that the battery has been changed.

If, after all this change, the vehicle does not start, we should check that the battery is properly connected and the car terminals are tight, that the ground connection is correct and that the specifications of the new battery are similar to the specifications of the battery we have replaced.

Step 5. Maintenance Tips

To maintain a battery correctly and to avoid problems, you should bear in mind that it is often the maintenance of a battery in a discharged state that will damage a battery.

If the battery is discharged occasionally and then recharged, the effect will be negligible. However, if we discharge the battery and keep it in a discharged state for a long time, we can damage the battery.

But why does a battery fail if it is kept in a discharged state?

When a battery is discharged it starts to generate sulphate. This sulphate is harmful to the battery and reduces its performance. The deeper the discharge, the faster the sulphate is generated and the faster the battery will deteriorate.

Furthermore, when a battery is damaged for this reason, it is considered to be misuse and the manufacturers do not accept this as a warranty. This is because a battery must always be kept on charge.

It is also useful to know that under normal circumstances, when a vehicle is stationary, there is always latent consumption that discharges the battery: If, in addition, the vehicle has an electrical problem, the consumption could be higher and discharge the battery in one or two days.

On the other hand, if we disconnect the battery, there is also a minimal self-discharge, although much less than if it were connected to the car.

To summarise all of the above, we give the following advice:

- If a battery is discharged occasionally (for example, if a light is left on), it should be charged as soon as possible.

- If we are not going to use the vehicle for a long time, we should charge the battery to the maximum and disconnect it, if possible. If this is not possible, charge it every few minutes.

- If our vehicle has a higher consumption than normal, we should fix the consumption problem as soon as possible, otherwise it will be continuously discharging the battery. We recommend taking the car to a garage specialising in this type of problem.

Idea: Always keep the battery charged.