Experiencing issues with your 2015 Mercedes S550 key fob? A common culprit is often the key fob battery. You might be getting a low battery warning on your dashboard, or perhaps your keyless entry is becoming less responsive. Replacing the battery is a straightforward DIY task, but surprisingly, the brand of battery you choose can make a difference, especially for Mercedes-Benz vehicles.
The standard battery for most Mercedes key fobs, including the 2015 S550, is the CR2025 3V lithium battery. These batteries are widely available and adhere to industry specifications. However, some Mercedes-Benz owners have reported encountering persistent “low battery” warnings even after replacing the battery with a new CR2025. This leads to the question: are all CR2025 batteries truly equal when it comes to Mercedes key fobs?
One Mercedes owner decided to investigate this issue after experiencing similar problems. After experimenting with different brands, they discovered an interesting result. Official Mercedes-Benz parts batteries, which are actually manufactured by Panasonic Industrial, seemed to resolve the low battery message immediately. Switching back to other brands, like Maxell, brought the warning message back.
Intrigued, further testing was conducted with off-the-shelf Panasonic CR2025 and CR2032 batteries. Remarkably, these also worked without triggering the error message. This suggests that the key might not be simply the “Mercedes” branding or an “industrial” specification, but rather the Panasonic brand itself. Batteries from brands like Maxell and Energizer, despite meeting the CR2025 specifications, appeared to cause the error message in this particular Mercedes S550 key fob.
This phenomenon isn’t unique to Mercedes-Benz. BMW owners have reported similar experiences and have also found Panasonic batteries to be a reliable solution for their key fobs. While the exact technical reason for this brand sensitivity remains unclear, it’s not simply a matter of voltage. Voltage testing showed that different brands had slightly varying voltage readings, but the Panasonic batteries, even with slightly lower voltage readings than some other brands, consistently worked in the Mercedes key fob without issue.
Step-by-Step Guide to Replacing Your 2015 Mercedes S550 Key Fob Battery:
While specific instructions can vary slightly depending on your exact key fob model, here’s a general guide for replacing the battery in your 2015 Mercedes S550 key fob:
- Locate the battery compartment: On most Mercedes key fobs, there’s a small release latch or button. You may need to slide or press this to access the battery compartment. Refer to your owner’s manual for precise instructions for your specific key fob.
- Open the key fob: Once you’ve located the release, carefully open the key fob casing. You might need a small flathead screwdriver or a similar tool to gently pry it open.
- Identify the battery: The CR2025 battery will be visible inside the compartment. Note the battery orientation (+ side up).
- Remove the old battery: Gently remove the old battery. You can usually do this with your fingertip or the small screwdriver.
- Insert the new battery: Place the new Panasonic CR2025 battery into the compartment, ensuring the correct orientation (+ side up).
- Close the key fob: Carefully reassemble the key fob casing until it clicks securely closed.
- Test your key fob: Test the key fob functions to ensure the new battery is working correctly and that the low battery warning has disappeared.
Recommended Battery Brand:
Based on owner experiences, Panasonic CR2025 batteries are highly recommended for 2015 Mercedes S550 Key Fob Battery Replacement. While other CR2025 batteries might function, choosing Panasonic appears to be the most reliable way to avoid potential issues with low battery warnings and ensure optimal key fob performance. When replacing your Mercedes key fob battery, opting for the Panasonic brand can save you potential headaches and ensure your key fob operates flawlessly.
