Need professional repair instead?

UpFix can fully rebuild BMW E-Series key fobs, including micro-soldering, battery replacement, and complete function testing for far less than dealership pricing.

Restore your BMW key fob the right way. Send it to UpFix for a complete rebuild and reliable long-term performance.

Understanding BMW Soldered Key Fob Batteries

BMW’s E-Series key fobs differ from the later F-Series and G-Series keys. Those newer keys often allow easier battery service, but the older E60, E87, and E90 keys do not. Their internal rechargeable battery is permanently soldered to the printed circuit board.

This means:

• The battery is not designed as a user-replaceable component

• Removing it requires proper soldering and desoldering tools

• Excess heat can damage surrounding components

• Misalignment during installation can prevent proper key reassembly

• Pressing too hard on the button domes can crush or dislodge them

Affected platforms include:

• BMW E60 5-Series

• BMW E87 1-Series

• BMW E90 3-Series

• Other E-chassis keys using VL-type rechargeable cells

When these batteries fail, the key may stop charging entirely. Replacement is possible, but only with the correct approach.

Tools You Need for a Proper Battery Replacement

Ernest uses the following tools during the demonstrated repair:

• Reverse tweezers for securing the circuit board or battery

• Solder wick for removing old solder

• Optional desoldering pump

• Fine-tip soldering iron suitable for PCB-level work

• Replacement 3V rechargeable battery (3VT with solder tabs)

The replacement battery must match the original tab layout. It is designed to fit only one way, but placement accuracy still matters.

Avoid guesswork and costly dealership replacements. Start your key fob repair with UpFix today.

Common Mistakes and How to Avoid Them

Because BMW E-Series keys use delicate components, there are several mistakes that can cause permanent damage. Below are the most frequent issues and how to prevent them.

Overheating the Circuit Pads

Using excessive heat or keeping the iron on the pad too long can lift the copper traces. Always use a temperature-controlled iron and brief contact times.

Crushing the Button Domes

The metal domes under the buttons are extremely thin and can dent or move. Avoid pressing on them during soldering or while securing the board.

Installing the Battery at an Angle

A battery that isn’t seated flush will prevent the key housing from closing fully. This also stresses the solder joints over time.

Leaving Solder Debris or Bridges

Stray solder can short out circuits or interfere with button operation. Always use solder wick to clean excess material.

Incorrect Polarity

While the tab layout helps prevent this, forcing the battery into the wrong orientation can permanently damage the board.

Avoiding these mistakes ensures the new battery functions correctly and the key remains structurally sound.

Need professional repair instead?

UpFix can fully rebuild BMW E-Series key fobs, including micro-soldering, battery replacement, and complete function testing for far less than dealership pricing.

Restore your BMW key fob the right way. Send it to UpFix for a complete rebuild and reliable long-term performance.

When a BMW Key Fob Needs More Than a Battery

Not all BMW key issues come from a failing rechargeable cell. These fobs contain multiple sensitive components that can fail independently. If your key still has issues after replacing the battery, one of the following may be the cause:

Worn or Damaged Button Contacts

Over time, the metal domes can lose their responsiveness or detach entirely.

Cracked Solder Joints

A drop or impact can crack solder points, causing intermittent or complete failure of certain functions.

Damaged Charging Coil

If the inductive charging coil is damaged, the new battery will never recharge, even though the cell itself is good.

Water Intrusion

Water or moisture can corrode traces and cause long-term degradation.

Broken Housing Clips

If the shell can’t close tightly, the internal board may shift and disconnect from the battery tabs.

If any of these issues are present, the key may require PCB repair, component replacement, or housing restoration instead of just a new battery.

FAQs

Do BMW E-Series keys recharge while driving?

Yes. The inductive coil inside the vehicle charges the battery while the key is inserted.

Is it possible to replace the battery without soldering?

No. The E-Series battery is permanently soldered and requires micro-soldering tools to remove.

What if I accidentally remove a pad or damage a dome?

The key can still be repaired in most cases with professional PCB work.

How long should a new rechargeable battery last?

Typically seven to ten years, depending on driving frequency.

Yes, but remote lock/unlock and comfort access features will stop working.

Conclusion

BMW E-Series key fobs are durable, but their soldered rechargeable batteries eventually wear out. Replacing the battery requires precision soldering, careful handling, and an understanding of how delicate the internal components are.

By following Ernest’s step-by-step method, DIY users can attempt the repair safely. However, many key fobs also suffer from additional issues such as worn buttons, cracked joints, or charging coil failures—problems that go beyond simple battery replacement.

For complete restoration or if you prefer a professional outcome, UpFix can handle the entire key fob rebuild process, ensuring every component is repaired, tested, and functioning as intended.

If you’d like, I can refine these replacement sections further or add alternative sections such as “Maintenance Tips,” “How BMW Charging Coils Work,” or “Troubleshooting Remote Range Issues.”

If your BMW key is failing, don’t wait for it to leave you stranded. Submit your repair order and let UpFix bring it back to full function.