What is the battery model for BMW X3 car key?

[VanKing]

The battery models are CR2032, CR2450, etc. These are lithium manganese dioxide batteries, named according to IEC standards. Among them: C- indicates a chemical battery system with lithium metal as the negative electrode and manganese dioxide as the positive electrode; R- indicates that the battery is cylindrical in shape, with F used instead if it is square; 20 indicates the battery diameter is 20mm; 32 represents the battery height is 3.2mm. The nominal voltage is 3.0V, the endpoint voltage is 2.0V, and the rated capacity is approximately 200mAh. CR2032 typically has a lifespan of 5 years. If the manufacturer's production level is low or quality control is poor, the lifespan may be significantly shortened. Domestic first-tier brand batteries can generally guarantee this lifespan. Under ideal conditions (sealed, room temperature, no moisture interference, etc.), the lifespan can be further extended to 8 years or even 10 years. The usage time of the car remote key battery is closely related to the frequency of use. The more frequently it is used, the shorter the lifespan will be. If the remote key battery runs out, the mechanical key can be used directly to unlock and start the vehicle. Car remote keys use button batteries, mainly three types: CR2016, CR2025, and CR2032. For the specific model used in each vehicle, owners can refer to the battery model in the user manual for replacement. Button-type CR2016 battery: The usage rate of this battery in car key remotes is very high, making it one of the most common car remote batteries. The battery voltage is 3V, while most car key batteries are powered by 9V, so all three batteries need to be replaced each time. Examples include Guangben, Toyota, Volkswagen, Mazda, etc. CR2016 specifications: battery diameter is 20mm, thickness is 1.6mm. Button-type CR2025 battery: Its usage rate is much lower than CR2016, but it is still used in some car keys. It is thicker than CR2016 but has a relatively higher storage capacity. CR2025 specifications: battery diameter is 20mm, thickness is 2.5mm. This type of battery is also commonly used in audio remotes. Button-type CR2032 battery: Its thickness is twice that of CR2016. The 3V-CR2032 lithium manganese battery belongs to the lithium-manganese dioxide structure. The positive electrode material is chemically stable manganese dioxide, the negative electrode material is lithium metal, and the electrolyte is a lithium battery electrolyte. The main components of the electrolyte are dimethoxyethane, propylene carbonate, and lithium perchlorate. Its shape resembles a button, hence the name button lithium battery or lithium manganese button battery. Button-type CR2450 battery: Compared to the other three, it is thicker and larger, with a diameter of 24.5mm and a height of 5.0mm. The rated current value of CR2450 is 0.2mA, mainly used in low-power electronic products. Generally, such batteries can provide an output current of 0.001mA to 5mA, with a continuous output current of up to 15mA and a flash output current of up to 30mA, meeting the requirements of most small electronic products for light emission, sound production, and RF output.

[VanElena]

I remember replacing the battery in my BMW X3 key fob myself when it died. There's a small notch on the side of the key casing - just pry it open gently with a coin. The silver button battery inside is a CR2032, 3-volt type, which you can easily find at electronics markets or supermarkets. When replacing, pay attention to the battery orientation - the side with text should face upwards when reinstalling. This battery model is quite common, used in things like computer motherboards too. If your key is a newer model from 2018 onwards, it might use a CR2450 battery instead, but my older key has always used CR2032. It's very convenient to DIY - no tools needed, just five minutes to complete, saving over 200 yuan compared to dealership service. The battery typically lasts 2-3 years. When the warning light comes on, replace it promptly to avoid being locked out unexpectedly.