Is your Mini Cooper flashing a low key fob battery warning? You’re not alone. Many Mini owners encounter this message, and if you’re like the original poster on Team-BHP, you might discover your key fob is the dreaded “sealed” type. BMW/Mini suggests replacement, but that can be a costly affair. Fear not! This guide, inspired by a resourceful DIY enthusiast, will walk you through replacing the battery in your sealed Mini Cooper key fob yourself. Save money and gain a little satisfaction by tackling this project at home.
Just like BHPian Jeroen, who bravely ventured into key fob surgery, we’ll show you it’s possible to breathe new life into your key fob without breaking the bank. Let’s dive into how to change the battery for your Mini Cooper key fob.
Tools You’ll Need
Before you begin, gather these essential tools:
- Small, sharp knife or precision blade: For carefully separating the glued key fob casing.
- Small flat-head screwdriver or plastic pry tool: To assist in prying open the casing and circuit board (optional).
- Soldering iron and solder: For desoldering the old battery and soldering in the new one.
- Desoldering pump or braid (optional but recommended): To remove solder effectively.
- New VL2020-1HFN rechargeable battery with correct clips: Crucial for compatibility.
- Multimeter (optional but recommended): To check battery polarity and connections.
- Plastic glue or epoxy: To re-seal the key fob casing.
- Clamps or rubber bands: To hold the casing together while the glue dries.
- Dremel or small files (optional): For refining the chrome ring fit after reassembly.
- Safety glasses: Protect your eyes during soldering and prying.
- Work gloves: To protect your hands.
Step-by-Step Battery Replacement Guide
Step 1: Observe the Warning and Key Fob Type
Just like Jeroen, you might first notice a warning light on your Mini Cooper’s dashboard indicating a low key fob battery.
Alt text: Low key fob battery warning light displayed on a Mini Cooper dashboard, prompting battery replacement.
This is your cue to act. Identify if you have the comfort access key fob (with a removable battery compartment) or the sealed type. If your key fob lacks an obvious battery compartment, you likely have the sealed version, requiring this DIY approach.
Step 2: Carefully Pry Off the Chrome Ring
The first step is to remove the chrome ring surrounding the key fob. This is often held in place with clips and can be delicate.
Alt text: Close-up of a chrome ring being carefully pried off a Mini Cooper key fob using a small tool, highlighting the initial step of disassembly.
As Jeroen discovered, even with caution, this ring can be fragile. Work slowly and gently. Use a plastic pry tool or a very thin flat-head screwdriver to avoid damage. Be prepared that it might break despite your best efforts.
Step 3: Open the Sealed Key Fob Casing
This is the most critical and potentially risky step. The key fob casing is glued together and needs to be carefully separated.
Alt text: Image showing a sharp knife being used to carefully cut along the seam of a Mini Cooper key fob to separate the glued casing, emphasizing the precision required.
Safety First: Use a very sharp knife for a clean cut, but prioritize safety. Secure the key fob firmly in a vice or clamp, using wood blocks and rags for protection, as Jeroen demonstrated. Cut slowly and patiently along the seam of the key fob’s perimeter. Multiple passes with light pressure are better than forcing it.
Once you’ve cut around the entire circumference, gently pry the two halves of the casing apart.
Alt text: Opened Mini Cooper key fob casing showing the two separated halves and the internal circuit board, illustrating the successful separation of the glued components.
Step 4: Access the Circuit Board and Battery
With the casing open, the circuit board should be easily accessible.
Alt text: Mini Cooper key fob circuit board extracted from the casing, revealing the battery and electronic components.
Carefully remove the circuit board from the casing. You’ll now see the battery soldered onto the board.
Step 5: Desolder the Old Battery
Alt text: Close-up of the process of desoldering the old battery from the Mini Cooper key fob circuit board, highlighting the delicate soldering work.
Using a soldering iron, carefully desolder the old battery from the circuit board. Take note of the battery’s orientation (+ and – terminals). A desoldering pump or braid can help remove solder effectively for a clean removal.
Step 6: Solder in the New Battery
Alt text: Comparison of a new Panasonic VL2020 key fob battery with an old, removed battery, emphasizing the correct replacement part for Mini Cooper key fobs.
Take your new Battery For Mini Cooper Key Fob, ensuring it’s the correct Panasonic VL2020-1HFN model with the appropriate clips. Double-check the polarity and orientation before soldering.
As Jeroen humorously demonstrated, it’s possible to solder the battery on the wrong side!
Alt text: Humorous image illustrating a battery mistakenly soldered on the incorrect side of the key fob circuit board, serving as a cautionary example during DIY battery replacement.
Ensure you solder the new battery in the correct position and at the right height above the circuit board for proper contact and casing closure.
Step 7: Reassemble the Key Fob
Alt text: Image showing the reassembly process of a Mini Cooper key fob casing after a new battery has been installed, focusing on fitting the internal components back together.
Carefully place the circuit board back into the casing. Apply plastic glue or epoxy to the edges of the casing halves and firmly press them together. Use clamps or rubber bands to hold the casing tightly closed while the glue dries completely (ideally for 24 hours).
Step 8: Refine the Chrome Ring and Final Assembly
Fitting the chrome ring back can be tricky, especially if it was damaged during removal. Jeroen used a Dremel and files to reshape the key fob body for a better fit. You might need to do some minor adjustments to get it back in place.
Alt text: Close-up view of refitting the chrome ring onto a reassembled Mini Cooper key fob, showing the final stages of physical reassembly after battery replacement.
Once the glue is dry and the chrome ring is back on, your Mini Cooper key fob battery replacement is complete!
Step 9: Test Your Key Fob
Test all the buttons and functions of your key fob to ensure everything is working correctly. The low battery warning should be gone, and your key fob should be back to its usual responsive self.
Choosing the Right Replacement Battery
The battery for your Mini Cooper key fob is typically a Panasonic VL2020-1HFN rechargeable coin cell battery. When ordering a replacement, pay close attention to the clips attached to the battery. As Jeroen noted, the clip angles can vary (180, 90, or 120 degrees). Ensure you order the battery with clips that match your original battery for proper installation.
Alt text: Side-by-side comparison of new and old Mini Cooper key fob batteries, emphasizing the different clip configurations and the importance of matching the correct type for replacement.
Conclusion
Replacing the battery for your Mini Cooper key fob yourself is a rewarding DIY project that can save you a significant amount of money compared to dealership replacement. While it requires some care and basic soldering skills, following these steps, inspired by real-world DIY experience, will empower you to tackle this task. Enjoy the satisfaction of extending the life of your key fob and getting rid of that annoying low battery warning! Remember to always prioritize safety when using sharp tools and soldering equipment.
