What is the battery model for BMW car keys?
2 Answers
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 the battery shape is cylindrical, if it is square, F is used instead; 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 around 200mAh. CR2032 typically has a lifespan of 5 years. If the manufacturer's production level is low or quality control is poor, its lifespan will be significantly shortened. Domestic first-tier brand batteries can generally guarantee this lifespan. If the usage environment is ideal (sealed, room temperature, no moisture interference, etc.), the lifespan can be further extended 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 usage time will be. If the remote key battery runs out of power, the mechanical key can be used directly 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 case, car owners can refer to the battery model in the user manual for replacement. Button-type CR2016 battery: The usage rate of car key remotes is very high, and it is one of the most common car remote batteries. The battery voltage of this type is 3V. Generally, 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 20mm, thickness 1.6mm. Button-type CR2025 battery: Its usage rate is much lower than CR2016. However, some car keys still use it. It is thicker than the 2016 model 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 battery CR2032: 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 very stable manganese dioxide, the negative electrode material is lithium metal, and the electrolyte is a lithium battery. The main components of the electrolyte are ethylene glycol dimethyl ether, propylene carbonate, and lithium perchlorate. It is shaped like a button, hence the name button lithium battery or lithium manganese button battery. Button battery CR2450: 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, the battery 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.
Speaking of BMW key fob battery models, my personal experience was when my BMW 3 Series key suddenly stopped working, which really stressed me out. After checking the manual and online forums, I found that most BMW keys use CR2032 coin batteries. Confirming this is simple—just flip the key over, as there’s usually a label with the model number, or you can open the back cover to see the code on the old battery. I bought a CR2032 at the supermarket for less than five yuan, and the whole process took under two minutes: use a coin to pry open the cover, remove the old battery, align the new battery with the correct polarity, snap the cover back on, and test it. Remember to buy branded batteries like Panasonic or Energizer—avoid no-name brands to prevent premature failure. Key fob batteries typically last one to two years, so it’s wise to check the power level at least every six months to avoid getting stranded. Keep a spare battery in your car just in case—it’ll save you from being stuck.
