What is the battery model for BMW key?
2 Answers
The battery model is CR2032. It is a lithium manganese dioxide battery, named according to the IEC standard. 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 for square batteries; 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, its lifespan can be significantly shortened. Domestic first-tier brand batteries can generally guarantee this lifespan. Under ideal conditions (sealed, room temperature, no moisture, etc.), the lifespan can extend further to 8 years or even 10 years. The usage time of a car remote key battery is closely related to the frequency of use. The more frequently it is used, the shorter the lifespan. If the remote key battery runs out, you can directly use the mechanical key to open and start the vehicle. The batteries used in car remote keys are 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: This is one of the most commonly used remote key batteries. The battery voltage is 3V, while most car key batteries operate at 9V, so all three batteries need to be replaced each time. Examples include brands like Honda, Toyota, Volkswagen, and Mazda. CR2016 specifications: battery diameter 20mm, thickness 1.6mm. Button-type CR2025 battery: Its usage rate is much lower than CR2016, but some car keys still use it. It is thicker than CR2016 but has a relatively higher storage capacity. CR2025 specifications: battery diameter 20mm, thickness 2.5mm. This type of battery is also commonly used in audio remotes. Button-type CR2032 battery: It is twice as thick as 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 is metallic lithium, and the electrolyte is a lithium battery electrolyte. The main components of the electrolyte are dimethoxyethane, propylene carbonate, and lithium perchlorate. It is shaped like a button, hence the name lithium button 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 for CR2450 is 0.2mA, mainly used in low-power electronic products. Generally, these batteries can provide an output current of 0.001mA to 5mA, with a continuous output current of up to 15mA and a pulse output current of up to 30mA, meeting the requirements for light emission, sound, and RF output in most small electronic products.
My BMW has been driven for several years, and the key has recently become unresponsive. After checking, I found that the battery is a CR2032 coin cell. I've replaced it myself a few times, and it's quite simple: first, eject the mechanical key from the main body, then use a small tool to gently pry open the back cover. Remove the old battery, remember to place the new one with the positive side facing up, and then close the cover. The whole process takes no more than ten minutes, and the battery can be bought at a supermarket or online for just a few dollars. The battery typically lasts about one to two years, and if you frequently use the key for remote start or locking, it may deplete faster. Common symptoms of a low battery include unresponsive buttons, a warning light on the dashboard, or reduced remote control range. Address it early to avoid being locked out. By the way, different BMW models may have slight variations in the key design—for example, older X5 models might have a slightly different battery placement. Checking the manual can provide extra reassurance.
