Is your Mercedes-Benz not starting due to a dead battery? Learn how to fix the problem by replacing the main battery of your Mercedes-Benz S-Class.

It is important to point out that for model years 2007 and 2008, the battery is a smaller battery (Group Size V4) used only for starting the engine. The larger Group Size 49 battery is behind the rear seat for those model years.

In 2009 models, Mercedes-Benz moved the larger battery from behind the rear seat to the engine bay starting with the model year. It replaced the smaller starter battery used in 2006-2008 models. The battery in the engine bay is used to crank the engine and supply power to the onboard electrical system.

From 2010-2013 S400 hybrid models remained behind the rear seat while the hybrid battery was on the engine bay and passenger side. A secondary battery (Part Number N000000004039 12 Volt 1.2Ah) is located under the dashboard. This is known as the auxiliary battery and is primarily used for ensuring the vehicle can shift to Park even if the main battery fails.

What you will need

  • Battery
    The battery size is different for pre-2009 models.


    • 2009-2013 CL/S Class
    • 2006-2008 CL/S Class
      • Group Size V4

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        • This battery is difficult to find. There are not many parts stores that sell a Group V4 battery. Because the compartment is larger than the existing battery, we have retrofitted a Group Size 65 battery without a problem. Group size 65 batteries are cheap, but if you want to install an OEM battery, your best choice is to buy the dealer’s battery. OEM V4 battery part number: A 230 541 00 01
  • 10mm and 13 sockets
  • 3/8″ Ratchet
  • Battery Terminal Brush


  1. Park your Mercedes-Benz S-Class or CL-Class in a safe working environment, set the parking brakes, and remove the key from the ignition.
  2. Pull the hood release under the hood of your S Class.
  3. Open the hood and locate the battery on the passenger side of the engine bay. w221 s550 s600 cl550 battery main engine bay
  4. Disconnect the negative terminal first by loosening the 10mm bolt. The bolt does not need to be removed. w221 negative battery terminal
  5. Disconnect the positive terminal next. W221 positive battery terminal
  6. Remove the 10mm nut and remove the top bracket. battery bracket s550  2006 2007 2008 2009 2010 2011 2012 2013
  7. Remove the 13mm bolt on the side of the battery. Remove side bracket. S CL Class Battery Location and bracket
  8. Lift the old battery out and place the new Group Size 49 battery in place. mercedes battery replacement
  9. Clean the battery terminal using a battery terminal brush.
  10. Install side and top bracket.
  11. Connect the positive battery terminal.
  12. Connect the negative battery last.
  13. Start your car and ensure all is working properly.
  14. Synchronize windows, sunroof, and steering-able sensors by moving these parts up/down (left/right).

I don’t have a large battery in the engine bay

Battery Location Mercedes S Class 2006 2007 2008

2006-2008 model years have the main battery behind the rear seat. It can be accessed via the trunk. See our tutorial on how to replace that battery.

We hope you find the 2009-2013 Mercedes S-Class Main Battery Replacement guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

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