Have you ever noticed your car key fob’s range decreasing? It’s a common frustration, often signaling a low battery. While some vehicles offer convenient in-car wireless charging, this isn’t always practical, especially if you don’t have a garage or easy access to your car. Keeping your key fob charged is essential for optimal range and function. Let’s explore how to charge your key fob effectively, even without relying solely on your vehicle.
Understanding Key Fob Charging Needs
Modern key fobs, especially those for vehicles with features like remote start and keyless entry, rely on battery power. Some key fobs utilize non-rechargeable batteries that need replacement, while others, particularly in luxury brands, incorporate rechargeable batteries designed to be charged. BMW, for example, suggests in-car wireless charging for their key fobs. However, this method isn’t always accessible or convenient for everyone. A discharged key fob can lead to a significantly reduced operating range, making it necessary to hold the fob very close to the car for it to function.
Exploring Home Charging Solutions
If in-car wireless charging isn’t an option, you might be looking for alternative ways to charge your key fob at home. One approach involves inductive charging, the same technology used in wireless phone chargers and electric toothbrushes. Experimenting with an Adafruit Induction charging set can provide insights into how these systems work and if they can be adapted for key fobs.
Initial investigations into inductive charging for key fobs reveal that optimal placement is crucial. Positioning the key fob with the brand logo (like the BMW roundel) facing the inductive charging loop tends to yield the best results, maximizing current draw and potentially faster charging. This suggests that the internal charging coil within the key fob is strategically positioned.
For those curious about the internal design of in-car key fob chargers, disassembling an old unit could be insightful. Understanding the coil positioning and voltage regulation within a factory car charger can help refine DIY charging attempts.
Battery Specifications and Charging Time
Many rechargeable key fobs, including some BMW models, use the Panasonic VL-2020 battery. This is a small rechargeable coin cell battery with a capacity of around 20mAh and a standard charge current of just 1.5mA. Based on these specifications, a full charge from empty should theoretically take well under 20 hours at this standard charge rate. Experimentation with inductive charging methods and readily available components can offer a practical solution for maintaining a charged key fob, ensuring you always have a reliable and long operating range.
