How Do You Replace the Battery on a Mercedes? (Easy Guide)

How Do You Replace the Battery on a Mercedes? (Easy Guide)

The battery on a Mercedes-Benz is essential for starting the car and keeping all electrical systems running smoothly.

However, Mercedes batteries must be replaced every four to five years.

If your battery is due for a replacement, we’ve good news for you:

Anyone can replace a Mercedes battery, and it doesn’t require special tools. Getting a new Mercedes battery replaced by the dealer can cost up to $700, but if you buy a genuine OEM battery and perform the replacement yourself, it may cost as little as $200.

5 Steps to replace a Mercedes-Benz battery

If your Mercedes displays a ‘Stop Vehicle Leave Engine Running’ message, it’s a sign that your battery is on its last legs and needs to be replaced:

Mercedes Stop Vehicle Leave Engine Running

Of course, it can also happen that your Mercedes won’t start due to a completely discharged battery.

Here is how to replace a Mercedes battery in five steps:

  1. Inform yourself about the safety precautions.
  2. Gather the necessary tools and the new battery.
  3. Locate the battery in your Mercedes.
  4. Remove the old battery.
  5. Install the new battery.

1. Inform yourself about the safety precautions

Before we jump into the nuts and bolts of battery replacement, let’s talk safety.

We know it’s boring, but it’s super important.

Here’s a quick overview of what you should know:

  • Avoid a terminal short. Perhaps the most important thing to remember during a Mercedes battery replacement is to prevent contact between the battery’s positive and negative terminals. Also, the positive contact of the battery mustn’t make contact with any metal parts of the car.
  • Turn off your Mercedes. It might sound obvious, but it’s easy to overlook. You don’t want the keys in the ignition when you’re working on the battery.
  • Be careful of metal objects. Here’s something many forget: remove any metal jewelry or watches before starting. These can conduct electricity and cause short circuits or even burns. Trust me, it’s better to be safe than sorry.
Mercedes battery replacement terminal short

2. Gather the necessary tools and the new battery

Great! Now that you know about the safety precautions, let’s gear up.

Here are the tools you need to replace a Mercedes battery:

  • 10 mm Socket Wrench: This is for disconnecting the battery cables from the positive and negative terminals.
  • 13 mm Socket Wrench: This one removes the bracket that holds the battery in place.
  • 8″ Extension (Optional): Depending on your Mercedes model, an 8″ extension for your wrench can be a real arm-saver here. If you struggle to reach the battery terminals or brackets, this will come in handy.
  • Battery Terminal Brush (Optional): If your car is a bit older or if you’ve noticed some corrosion around the battery terminals, this tool is a good idea. It helps clean the battery posts and ensures a good connection with the new battery.
  • Memory Saver Device (Optional): This gadget keeps your car’s electronic memory (like radio presets, clock settings, and memory seats) alive while you swap out the battery. It’s not essential, but it’s nice to have if you don’t want to reset everything afterward.

If you’re buying the replacement battery yourself, you should also keep in mind to buy the correct one.

AutoZone has a special filter that allows you to enter your exact Mercedes model and find the ideal battery:

AutoZone Mercedes car battery finder

3. Locate the battery in your Mercedes

Now that you’ve got your tools ready, the next step is finding the battery in your Mercedes.

The most common Mercedes battery location is under the hood, near the windshield, completely on the left or right side. However, depending on your model, the battery might also be in the trunk or even under the rear seat.

Mercedes battery location - under the hood

Here is the battery location of some common Mercedes models:

  • Mercedes C250, C300, E350, E320, E400, S500, and S550: You’ll usually find the battery under the hood, on the right side (from the driver’s perspective), near the windshield.
  • Mercedes GLC300, CLA250, and GLA250: The starter battery is located under the hood. It’s usually on the left side (from the driver’s perspective), near the windshield, and under a plastic cover.
  • Mercedes GLE350, ML350, R350, and GL450: The battery for these models is located under the front passenger seat. You can access it from behind the front passenger seat by sliding the seat all the way forward and removing the plastic cover.

Note that some Mercedes models, like the C300, E350, or GLE350, have two batteries. In this case, the battery for the starter motor is usually located under the hood, while the auxiliary battery (which powers the car’s electrical systems) is located inside the front passenger footwell, in the trunk, or under the front passenger seat.

If your model isn’t listed here, or if you’re still unsure, your owner’s manual is your best friend. It will have a diagram showing exactly where the battery is located in your specific model.

For example, here is the battery location for the Mercedes GLE as shown by the owner’s manual:

Mercedes Battery location illustration from the owner's manual

4. Remove the old battery

Here is how to remove a Mercedes battery:

  1. Remove the plastic cover. Most (newer) Mercedes models have a plastic cover placed above the battery. It’s usually clipped in. Carefully remove it.
  2. Disconnect the battery terminals. Start with the negative terminal (it’s usually marked with a minus (-) sign or is black in color). Use your 10 mm socket wrench to loosen the terminal clamp. Once it’s loose, gently remove the clamp from the battery post. After that, do the same for the positive terminal (marked with a plus (+) sign or red in color).
  3. Remove the holding bracket. Next, you’ll need to remove the bracket that’s keeping the battery in place. Unscrew the 13 mm bolts holding the bracket. Don’t lose these bolts – you’ll need them to secure the new battery.
  4. Lift out the old battery. Batteries can be heavy, so be prepared for a bit of weight. Carefully lift the battery out. If it’s stuck or difficult to move, check to ensure you haven’t missed any securing components.
  5. Inspect the area. Once the old battery is out, take a moment to inspect the area. If you see any corrosion or debris, now is a great time to clean it up. A clean battery area can help extend the life of your new battery.

Tip: Many auto parts stores will take your old battery for recycling.

Low-voltage battery illustration

5. Install the new battery

Exciting times – you’re now ready to install the new battery in your Mercedes!

Here’s how to do it:

  1. Position the new battery. Gently place the new battery into the same spot where the old one was. Make sure it’s oriented correctly, with the positive and negative terminals in the right positions (the positive terminal near the positive cable, and the same for the negative). The battery should sit flat and secure in its tray.
  2. Secure the battery with the bracket. Reattach the holding bracket using your 13 mm socket wrench.
  3. Connect the terminals. Reconnect the battery terminals, but in reverse order from how you disconnected them. First, connect the positive terminal (the red or plus (+) one). Tighten the clamp with your 10 mm socket wrench. Then, move on to the negative terminal (the black or minus (-) one) and do the same. Be careful not to over-tighten, as this can damage the terminals.
  4. Test Your work. Start your Mercedes to ensure everything is working correctly. If it starts smoothly, that’s a great sign! If you’ve used a memory saver device, you can now remove it. Check that all your settings are as they should be.

And there you have it! You’ve successfully installed a new battery in your Mercedes.

FAQs about Mercedes battery replacement

Here are some popular questions we get about Mercedes battery replacements:

How much is a battery for a Mercedes-Benz?

A genuine Mercedes battery typically costs about $400. However, if you’re looking for a more budget-friendly option, an OEM (Original Equipment Manufacturer) battery would cost you around $200.

How long does a Mercedes battery last?

Generally, a Mercedes battery lasts for about four years. Of course, this can vary based on factors like usage, climate, and how well the battery is maintained.

How often do you replace a Mercedes battery?

It’s recommended to replace a Mercedes battery every three to five years. This timeframe ensures that your car’s battery remains reliable and performs well.

Where is the Mercedes auxiliary battery located?

In most cases, the auxiliary battery in a Mercedes is located under the floor panel or in a side compartment of the trunk. However, this can vary depending on the model.

What is an auxiliary battery for?

An auxiliary battery in a Mercedes-Benz primarily supports the transmission. It allows the transmission to shift from ‘Drive’ or ‘Reverse’ to park if power from the main battery is unavailable. It also supports the start/stop system and can power electronic systems while the engine is off.


Well done!

You’ve just successfully replaced the battery in your Mercedes-Benz.

That’s a big achievement, especially if it’s your first time doing something like this.

I hope you feel proud and a bit more connected to your car now.

It’s a great feeling, isn’t it?

Feel free to share your experience or ask any questions in the comments!

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