Key fobs have become indispensable in modern vehicles, offering convenience and security. However, a common concern arises when the key fob battery starts to weaken: how do you charge it? While BMW suggests an in-car wireless charging method by leaving the key in position 1 for an extended period, this isn’t always practical, especially for apartment dwellers without garage access. Let’s delve into the ways you can keep your key fob powered up and ensure it operates reliably.
Understanding Key Fob Battery Needs
Most modern key fobs are powered by small, non-rechargeable batteries, often CR2032 coin cells. These batteries typically last for a couple of years, depending on usage. However, some key fobs, particularly in luxury vehicles like BMW, utilize rechargeable batteries to power more advanced features like comfort access and remote start. These rechargeable key fobs present a different charging scenario.
Wireless Charging for Key Fobs: How Does it Work?
Some vehicles, like BMWs as mentioned in the original discussion, are equipped with inductive charging systems for their key fobs. This technology is similar to wireless charging for smartphones. The car has a built-in transmitter coil, and the key fob contains a receiver coil. When the key fob is placed in the designated charging area within the car (often the steering column or center console area and in position 1), an electromagnetic field is created, wirelessly transferring power to the key fob’s battery.
However, relying solely on the in-car wireless charging might be inconvenient. What if you are not driving frequently, or as highlighted, you lack easy access to your vehicle for extended charging periods?
Exploring Alternative Key Fob Charging Solutions
For those seeking alternative charging methods, especially for rechargeable key fobs, a few options emerge:
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DIY Inductive Charging: As explored in the initial investigation, utilizing aftermarket inductive charging kits like the Adafruit Induction charging set can be a viable path. These kits allow you to create your own wireless charging pad at home. By carefully positioning the key fob over the transmitter coil, you can induce a charge. Experimentation, as noted, suggests placing the key fob with the brand logo facing the charging loop for optimal current draw.
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Toothbrush Chargers (with caution): Anecdotal evidence suggests that some electric toothbrush chargers might be compatible with key fobs utilizing inductive charging. However, this approach requires caution. Voltage and current compatibility are crucial. Using an incompatible charger could potentially damage the key fob’s battery or charging circuitry. Thorough research and testing would be necessary before attempting this.
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Battery Replacement (for non-rechargeable fobs): If your key fob uses a standard non-rechargeable battery (like CR2032), the most straightforward solution is battery replacement. This is a simple process that usually involves opening the key fob casing, replacing the old battery with a new one of the same type, and reassembling the fob.
Key Fob Battery Details: Panasonic VL-2020
The original post mentions the Panasonic VL-2020 battery, often found in BMW key fobs. This is a rechargeable coin-type battery with a 20mAh capacity and a standard charge current of 1.5mA. This information is crucial for understanding charging times. Theoretically, a full charge could be achieved in under 20 hours at this standard charge rate. This aligns with BMW’s 24-hour in-car charging suggestion, although faster inductive charging methods might reduce this time.
Conclusion: Keeping Your Key Fob Powered
Charging a key fob depends largely on the type of battery it uses. While in-car wireless charging is a feature in some vehicles, alternative methods like DIY inductive charging solutions can offer flexibility. For key fobs with standard batteries, simple battery replacement remains the easiest solution. Understanding your key fob’s battery type and charging requirements is the first step in ensuring it remains powered and your car access stays seamless. Further research into specific key fob models and compatible chargers is always recommended for safe and effective charging practices.
