Is your Mini Cooper key fob displaying a low battery warning? Don’t rush to the dealership just yet! If your Mini, like many, doesn’t have the comfort access package, you might think you’re stuck with a sealed key fob and forced to buy an expensive replacement from BMW/Mini. However, as a fellow car enthusiast, I’m here to tell you that changing the battery yourself is absolutely achievable.
In this guide, we’ll walk you through a step-by-step process on how to replace the battery in your non-comfort access Mini key fob. It’s a DIY project that can save you a significant amount of money and give you the satisfaction of fixing it yourself. Let’s dive in!
You might be wondering, what exactly is a “fob” anyway? The term “fob” actually originates from watch fobs, ornaments attached to pocket watch chains dating back to the late 19th century. In the context of car keys, it refers to the small, handheld remote device – your key fob!
Now, back to our Mini key fob battery issue. The original poster, BHPian Jeroen, encountered the dreaded low battery warning on his Mini’s dashboard:
Alt: Low battery warning symbol illuminated on a Mini Cooper dashboard indicating key fob battery replacement needed.
This warning signals that the battery inside your key fob is nearing the end of its life. While Mini offers key fobs with easily replaceable batteries in their comfort access package, those without are sealed, seemingly discouraging DIY battery changes. But fear not! We’re going to show you how to tackle this.
Before we begin, let’s take a closer look at the type of key fob we’re dealing with. This is a typical non-comfort access Mini key fob:
Alt: Image of a sealed Mini Cooper key fob showing the chrome trim, key buttons, and the hidden emergency mechanical key.
As you can see, there are no obvious screws or compartments to access the battery. However, there’s always a way! Even if the battery completely dies, Mini thoughtfully includes a mechanical key within the fob to unlock your car:
Alt: Close-up of a Mini Cooper key fob with the emergency mechanical key extracted, demonstrating manual car entry.
This mechanical key is a lifesaver, but for everyday convenience, a working key fob is essential. So, let’s get our hands dirty and change that battery!
Tools and Materials You’ll Need
Before you start, gather these essential tools:
- Sharp Knife or Precision Blade: A very sharp knife is crucial for carefully separating the glued key fob casing. The sharper, the cleaner the cut and the easier the process.
- Small Flathead Screwdriver or Pry Tool: For gently prying open the key fob halves once you’ve cut through the glue.
- Soldering Iron and Solder: To remove the old battery and attach the new one. If you are not comfortable with soldering, you might consider seeking help from someone with soldering experience.
- Replacement Battery: Identifying the correct battery is key. In this case, it’s a Panasonic VL2020-1HFN rechargeable BMW-Mini Battery. We’ll discuss finding the right replacement in more detail later.
- Electro Cleaner Spray (Optional): For cleaning the micro-switches inside the key fob.
- Plastic Glue or Epoxy: To re-seal the key fob casing after battery replacement.
- Clamps or Vise: To hold the key fob securely while cutting and gluing.
- Multimeter (Optional but Recommended): To check the polarity of the new battery and the old battery if needed.
- Dremel or Files (Optional): For refining the chrome ring fitting during reassembly.
- Safety Glasses: Always protect your eyes when working with tools and small parts.
Step-by-Step Guide to Change Your Mini Key Fob Battery
Now, let’s get to the heart of the matter: replacing the battery. Follow these steps carefully:
Step 1: Removing the Chrome Ring
The first step is to remove the chrome ring surrounding the key fob. This is often shown in videos as a simple prying action, but be warned, it can be fragile.
Alt: Image showing a broken chrome ring of a Mini Cooper key fob after attempted removal, highlighting potential fragility.
As you can see, even with extreme care, the chrome ring can break. Pry gently and patiently, working your way around the ring to minimize damage. Don’t worry too much if it breaks, it’s mostly cosmetic.
Step 2: Opening the Key Fob Casing
This is the trickiest part. The key fob casing is glued shut and needs to be carefully cut open.
Alt: Process of carefully cutting along the seam of a Mini Cooper key fob with a sharp knife, secured in a vise for stability and safety.
- Secure the Key Fob: Use a vise and wooden blocks or rags to hold the key fob firmly and safely. This provides stability and prevents injury.
- Carefully Cut Along the Seam: Using your sharp knife, carefully cut along the seam where the two halves of the key fob meet. Go slowly and apply steady pressure. Multiple passes are better than trying to cut through in one go.
- Work Around the Entire Circumference: Ensure you cut all the way around the key fob’s perimeter to fully separate the glued sections.
- Pry Open the Casing: Once you’ve cut deep enough, use a small flathead screwdriver or pry tool to gently pry the two halves of the key fob apart.
Alt: Two halves of a disassembled Mini Cooper key fob, showcasing the exposed internal circuit board and components.
Step 3: Accessing the Circuit Board and Battery
With the casing open, the circuit board should be easily accessible.
Alt: Extracted circuit board from a Mini Cooper key fob, ready for battery replacement procedure.
The circuit board usually comes out freely. Now you can see the battery attached to it.
Step 4: Desoldering the Old Battery
The battery is soldered onto the circuit board. Carefully desolder the old battery.
Alt: Close-up view of desoldering the battery terminals from the circuit board of a Mini Cooper key fob using a soldering iron.
- Heat the Solder Joints: Apply heat from your soldering iron to the points where the battery terminals are soldered to the circuit board.
- Remove the Battery: Once the solder melts, gently remove the old battery. You might need a solder sucker or desoldering wick to remove excess solder.
Step 5: Identifying and Ordering the Replacement Battery
Identifying the correct replacement battery is crucial.
Alt: Image of a Panasonic VL2020-1HFN rechargeable battery, the standard replacement for Mini Cooper non-comfort access key fobs.
The original battery is a Panasonic VL2020-1HFN rechargeable BMW-Mini Battery. Search online using this part number to find a replacement.
Important Considerations When Ordering:
- Battery Type: Ensure you order the VL2020-1HFN or equivalent rechargeable battery.
- Terminal Configuration: Pay close attention to the battery terminal configuration. As you can see, the positive (+) and negative (-) terminals are 180 degrees apart in this case. Some batteries might have terminals at 90 or 120 degrees. Order the one that matches your original battery.
Alt: Side-by-side comparison of a new and old VL2020-1HFN battery, emphasizing the alignment and configuration of battery terminals.
Step 6: Soldering the New Battery
Solder the new battery onto the circuit board in the correct orientation.
Alt: Image showing the incorrect initial soldering of the battery on the wrong side of the circuit board, a common mistake to avoid.
Common Mistake to Avoid: As shown in the image above, it’s easy to mistakenly solder the battery on the wrong side of the circuit board! Double-check the orientation before soldering.
Alt: Image illustrating the correctly soldered new battery on the circuit board of a Mini Cooper key fob, ensuring proper functionality.
- Correct Polarity: Ensure the positive (+) and negative (-) terminals of the new battery are aligned correctly with the markings on the circuit board. Use your multimeter to double-check if needed.
- Clean Solder Joints: Make clean and secure solder joints. Ensure the battery sits at the correct height above the circuit board for proper fitment in the casing.
Step 7: Reassembling the Key Fob
Now it’s time to put everything back together.
Alt: Process of carefully reassembling the two halves of the Mini Cooper key fob casing after successful battery replacement.
- Test the Mechanical Key Lock: Before gluing, test the mechanical key mechanism to ensure it works smoothly.
- Apply Glue: Apply plastic glue or epoxy to the edges of the key fob casing halves.
- Clamp the Casing: Clamp the two halves together and let the glue dry for 24 hours for a strong bond.
Alt: Clamped Mini Cooper key fob casing with glue drying, ensuring a secure and sealed enclosure after battery replacement.
Step 8: Refitting the Chrome Ring (Optional)
Refitting the chrome ring can be fiddly, especially if it broke during removal.
Alt: Image depicting the careful process of refitting the chrome ring onto a Mini Cooper key fob, potentially requiring reshaping for proper fit.
- Reshape if Necessary: If the ring is misshapen, use a Dremel or files to carefully reshape it for a better fit.
- Carefully Press into Place: Gently press the chrome ring back onto the key fob. It might not be a perfect fit if it was damaged, but you can aim for a reasonably snug fit.
Testing the Key Fob
Once reassembled, test your key fob!
Alt: Image of a successfully repaired Mini Cooper key fob, demonstrating a completed DIY battery replacement and restored functionality.
Hopefully, the low battery warning is gone, and your key fob is working perfectly again!
Tips and Warnings
- Sharp Knife Safety: Exercise extreme caution when using a sharp knife. Cut away from yourself and use a stable work surface.
- Soldering Skills: If you are not comfortable with soldering, consider practicing on scrap electronics first or seeking help from someone experienced. Incorrect soldering can damage the circuit board.
- Battery Polarity: Always double-check the battery polarity before soldering the new battery. Incorrect polarity can damage the key fob.
- Patience is Key: Take your time and be patient, especially when opening the casing and soldering. Rushing can lead to mistakes.
- Static Electricity: Be mindful of static electricity when handling the circuit board. Ground yourself if possible, although for this simple task it’s usually not critical.
Conclusion
Changing the battery in a non-comfort access Mini key fob might seem daunting, but with patience and careful execution, it’s a DIY task you can successfully accomplish. By following these steps, you can save yourself a significant expense and extend the life of your key fob. Enjoy the satisfaction of a job well done and the money saved!
This DIY guide provides a detailed walkthrough for replacing your Mini key fob battery. Remember to take your time, be careful, and enjoy the process of fixing things yourself!
