When you need to change a car battery? 
 

How to change a car battery step by step

Safety comes first here. Wear gloves and safety glasses to protect yourself from battery acid.

 

Always start by disconnecting the cable from the negative battery post to prevent any electrical shorts. any sparks or electrical issues. Then, disconnect the positive terminal.

 

 

Be careful not to allow any metal objects to touch both battery posts simultaneously. Also, don't let your wrench touch the positive terminal and the body or fender at the same time.

 

 

Remove any securing brackets or clamps that hold the battery in place. Lift the battery out of its tray carefully, as it can be quite heavy. Gloves will help protect you from any acid that might be on the battery.

 

 

Before placing the new battery in, make sure it’s fully charged. Remove the red and black plastic covers from the ends of the battery posts.

 

 

Place the new battery in the battery tray and secure it with brackets or clamps. Reconnect the terminals – this time, start with the positive terminal first, followed by the negative terminal. Make sure all connections are tight and secure. 

 

 

Now, after you change your car battery, that might just not be the end of the process.

 

For modern cars with start/stop system or intelligent battery sensors (IBS), a crucial step afterward is battery registration.

 

 

Car battery registration, also known as battery adaptation, is a programming procedure that informs your vehicle's electrical system that a fresh battery has been installed. 

 

It's crucial for modern cars equipped with advanced battery monitoring and start/stop systems, such as those found in Audi, Volkswagen, and BMW vehicles.

 

 

When you replace a car battery, the vehicle's battery management system (BMS) needs to know the specifications of the new battery to manage its charging and discharging cycles properly. Without this data, the vehicle won't be able to adjust and charge the battery correctly, resulting in faster battery wear or electrical malfunctions.

 

But what if you’re replacing your old battery with an identical one?

 

You still need to register it. Your BMS needs to know the battery is new so it can reset and recalibrate its monitoring.

 

 

Skipping car battery registration can lead to several issues – let us paint a picture for you.

 

 

Your car might either undercharge or overcharge the battery. Undercharging leads to sulfation, where the battery plates degrade, while overcharging can cause overheating and the loss of vital battery electrolytes.

 

Either way, it's like pushing your battery on a swing – too little or too much, and things go sideways, cutting its lifespan.

 

 

More so, your car's start/stop system might not function properly without proper registration. This oversight can increase fuel usage, as the engine won't shut off as usual.

 

 

Finally, skipping registration can open Pandora's box of electrical issues. You might see a rainbow of warning lights on your dashboard, experience blown fuses, or face system failures. In some cases, your car might not start at all.

 

 

For Volkswagen Group vehicles, like Volkswagen or Audi, you’ll need the OBDeleven NextGen device, the PRO VAG or the ULTIMATE VAG subscription, and the OBDeleven VAG mobile app.

 

 

Plug the device into your car's OBD2 port and connect your smartphone via Bluetooth.

 

Then, go to the list of control units. 

 

Here’s where the steps get different for VAG vehicles with the KWP2000 protocol and VAG models with the UDS protocol. We’ll refer to them as older VAG models and newer VAG models for clarity reasons.  

 

 

Scroll down to find the control unit called “Battery Regulation,” click on it, and select "Long Adaptation." Enter channel number 4 and hit “Done.” 

 

Tap on the "Value” field to input your battery information. Start with the first three digits for battery capacity, followed by a space.

 

Then, add the three symbols for the manufacturer code, another space, and the 10-digit serial number.

 

You can find these codes on a white sticker on the battery. If there’s no sticker, simply enter “UNK” for the manufacturer and change the last digit of the serial number. Then, confirm the changes.

 

If your new battery is different from the old one, take a few extra steps:

 

Go back to the “Battery Regulation” control unit and select “Long Coding.” Update the battery type to the correct one, then slide right to confirm.

 

 

For these newer models, the process is more straightforward. Once connected, find the control unit named “Gateway,” click on it, and choose "Adaptation."

 

Here, select "Battery adaptation" and fill in all fields with battery capacity, manufacturer, serial number (if you don't know, simply change the last digit), and battery technology. Slide right, and that's it.

 

 

Things are even simpler for BMW vehicles. You'll need the OBDeleven NextGen device and the OBDeleven app for this.

 

 

If your new battery type and capacity differs from the old one, navigate to "Apps," find the "Battery Type and Capacity" option, and select your new battery type. Skip this part if the type and capacity are the same.

 

Then, open the "12V Battery Registration" app, select the “RESET” option, slide, and you're set.

 

Check out our step-by-step video tutorial below for a more detailed visual walkthrough. It will guide you through battery replacement and registration so you can feel even more confident before doing it on your own.