Is your Mini Cooper flashing a low key fob battery warning on the dashboard? You’re not alone. Many Mini Cooper owners encounter this message, often leading them to believe a costly dealership visit is the only solution. While dealerships are quick to offer replacements, especially for sealed key fobs, you might be surprised to learn that replacing the battery yourself is not only possible but also quite straightforward with the right guidance.
This guide is for Mini Cooper owners who are told their key fobs are “sealed” and the battery cannot be replaced. Inspired by a fellow car enthusiast’s experience, we’ll walk you through a DIY Mini Cooper Key Fob Battery Replacement. Don’t let the “sealed” design intimidate you. With a bit of careful work and the right tools, you can easily restore your key fob’s power and save yourself a significant expense.
Understanding Your Mini Cooper Key Fob Battery
Mini Coopers, depending on the model and package, come with different types of key fobs. Some feature a “comfort package” which includes a key fob with a readily replaceable battery – a user-friendly design that simplifies maintenance.
However, if your Mini Cooper, like many, doesn’t have the comfort package, you’re likely dealing with a sealed key fob. These fobs lack an obvious battery compartment and are designed to be charged inductively when placed in the designated slot on your dashboard. BMW/Mini often suggests these batteries are not user-replaceable, pushing owners towards purchasing a new, expensive key fob.
But here’s the good news: even sealed mini cooper key fobs contain a standard rechargeable battery that can be replaced. This guide focuses on how to access and replace this battery, saving you money and empowering you to handle this maintenance task yourself.
Tools and Materials for Mini Cooper Key Fob Battery Replacement
Before you begin your mini cooper key fob battery replacement, gather the necessary tools and materials. Having everything prepared will make the process smoother and more efficient.
- New Battery: The original key fob uses a Panasonic VL2020-1HFN rechargeable battery. Search online for this specific model. Ensure the replacement battery has the correct clips (180-degree angle for this model, but double-check before ordering as variations exist).
- Small, Sharp Knife or Precision Blade: Essential for carefully separating the sealed key fob casing. A sharper blade will make cleaner cuts and reduce the risk of damaging the plastic.
- Small Flathead Screwdriver or Pry Tool: Helpful for prying open the key fob casing once you’ve cut through the sealant.
- Soldering Iron and Solder: Required to desolder the old battery and solder in the new one. If you’re new to soldering, practice on some scrap electronics first.
- Desoldering Pump or Braid (Optional): Can be helpful for removing excess solder when desoldering the old battery.
- Multimeter (Optional but Recommended): Useful for checking the polarity of the new battery and ensuring correct installation.
- Plastic Glue or Epoxy: To re-seal the key fob casing after the battery replacement.
- Clamps or Rubber Bands: To hold the key fob casing together while the glue dries.
- Electro Cleaner (Optional): For cleaning the micro-switches inside the key fob, potentially improving button responsiveness.
- Safety Glasses: Protect your eyes during disassembly and soldering.
- Work Gloves (Optional): To protect your hands.
- Vice and Wood Blocks (Optional): To securely hold the key fob during cutting (as shown in the original guide), providing stability and safety.
Step-by-Step Guide to Mini Cooper Key Fob Battery Replacement
Now, let’s dive into the mini cooper key fob battery replacement process. Follow these steps carefully, and remember to work in a well-lit area with a clean workspace.
Step 1: Removing the Chrome Ring
The first step is to remove the chrome ring surrounding the key fob. This ring is delicate and can break easily, as demonstrated in the original guide.
- Carefully pry around the edges of the chrome ring using a small flathead screwdriver or pry tool. Work slowly and gently to minimize the risk of damage.
- Note: Even with extreme care, the ring might still break due to its delicate nature. Don’t be discouraged if this happens; it’s a common issue.
Step 2: Opening the Sealed Key Fob Casing
This is the most crucial and potentially challenging step in the mini cooper key fob battery replacement. Take your time and prioritize safety to avoid injury.
- Secure the Key Fob: If you have a vice and wood blocks, use them to hold the key fob securely, as shown in the original guide. This provides a stable base for cutting and reduces the risk of slipping and cutting yourself. Alternatively, hold the fob firmly on a stable surface.
- Carefully Cut Along the Seam: Using your sharp knife or precision blade, carefully cut along the seam where the two halves of the key fob casing meet. Apply steady, even pressure. Multiple passes with light pressure are better than forcing the blade.
- Go Around the Circumference: Continue cutting around the entire circumference of the key fob until you have cut deep enough to separate the two halves.
- Pry Open the Casing: Once you’ve cut through the sealant, use a small flathead screwdriver or pry tool to gently pry the two halves of the casing apart. Work your way around the seam, gradually separating the halves.
Step 3: Accessing the Circuit Board and Battery
With the casing open, you’ll see the internal components of the mini cooper key fob.
- Circuit Board Removal: The circuit board should lift out easily. Handle it by the edges to avoid touching the components.
- Locate the Battery: The rechargeable battery (Panasonic VL2020-1HFN) is soldered onto the circuit board with metal clips.
Step 4: Desoldering the Old Battery
Now, you need to carefully remove the old battery from the circuit board.
- Heat the Solder Joints: Using your soldering iron, heat the solder joints connecting the battery clips to the circuit board.
- Remove the Solder: Once the solder is molten, use a desoldering pump or braid to remove the solder from the joints. If you don’t have these tools, you can try to gently wiggle and lift the battery as you heat the solder, but be careful not to damage the circuit board.
- Remove the Old Battery: Once the solder is removed, the old battery should lift off the circuit board.
Step 5: Soldering in the New Battery
With the old battery removed, it’s time to install the new mini cooper key fob battery.
- Position the New Battery: Place the new battery onto the circuit board, ensuring the polarity (+ and -) is correct. Double-check the orientation before soldering. Use a multimeter to verify if needed.
- Solder the Battery Clips: Solder the battery clips to the circuit board, making sure you create solid solder joints. Ensure the battery sits at the correct height above the circuit board for proper reassembly, as noted in the original guide.
- Inspect Solder Joints: Check your solder joints to ensure they are clean and secure.
Step 6: Reassembling the Key Fob
With the new battery soldered in, it’s time to reassemble your mini cooper key fob.
- Clean the Circuit Board (Optional): Before reassembly, you can use electro cleaner to spray and clean the micro-switches on the circuit board. This can improve button responsiveness.
- Test the Key Fob: Before gluing the casing back together, test the key fob to ensure it’s working. Insert the key into your Mini Cooper and check if the buttons function correctly.
- Apply Glue to the Casing: Apply a thin bead of plastic glue or epoxy to the edges of one half of the key fob casing.
- Reassemble the Casing: Carefully align the two halves of the casing and press them firmly together.
- Clamp the Casing: Use clamps or rubber bands to hold the casing tightly together while the glue dries completely (usually 24 hours).
- Refit the Chrome Ring: If you managed to remove the chrome ring without breaking it, carefully refit it. If it’s damaged, you can try to repair it with adhesive or leave it off. The functionality of the key fob is not affected by the chrome ring.
Tips for Success and Troubleshooting
- Patience is Key: Take your time and work carefully, especially when opening the sealed casing and soldering. Rushing can lead to mistakes or damage.
- Sharp Tools are Essential: A sharp knife makes cleaner cuts and reduces the force needed, improving safety and the finish.
- Double-Check Battery Polarity: Ensure the new battery is installed with the correct polarity (+ and -) to avoid damaging the key fob.
- Solder Correctly: If you are new to soldering, watch some tutorials and practice beforehand. Poor solder joints can lead to the battery not working or becoming loose.
- Test Before Gluing: Always test the key fob functionality before gluing the casing back together. This saves you from having to reopen the casing if something is wrong.
- If the Chrome Ring Breaks: Don’t worry if the chrome ring breaks. It’s primarily cosmetic. Focus on ensuring the key fob functions correctly.
Conclusion
Replacing the mini cooper key fob battery yourself is a rewarding DIY project that can save you a considerable amount of money compared to dealership replacement costs. While it requires some careful work, particularly in opening the sealed casing and soldering, following this step-by-step guide will empower you to successfully complete this task. By taking a proactive approach to car maintenance, you can keep your Mini Cooper running smoothly and your wallet a little heavier.
Remember to source the correct replacement battery (Panasonic VL2020-1HFN) and take your time throughout the process. With a little effort, you can conquer the “sealed” key fob and enjoy the satisfaction of a successful DIY repair.
