What is the battery model for the Mercedes-Benz C-Class 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 instead if it is square; 20 indicates the battery diameter is 20mm; 32 indicates 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 will 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 extended further, up to 8 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, the mechanical key can be used directly to unlock and start the vehicle. Car remote keys use button batteries, mainly in the following models: CR2016, CR2025, CR2032, and CR2450. For the specific model used in each key, 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 car remote batteries. The battery voltage is 3V, while most car keys operate on 9V, so three batteries need to be replaced each time. Examples include Honda, 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 is metallic lithium, 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 models, it is thicker and larger, with a diameter of 24.5mm and a height of 5.0mm. The rated current value for 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 burst output current of up to 30mA, meeting the requirements of most small electronic products for light, sound, and RF output.
I've been driving a Mercedes-Benz C-Class for several years and have replaced the key battery a few times. The battery model is usually the small, round CR2032, which is easy to find. I usually do it myself: use a small flathead screwdriver to gently pry open the back cover of the key, being careful not to apply too much force to avoid scratches. Then, remove the old battery and insert the new CR2032 with the positive side facing up—don’t put it in backward. The battery lasts about two years; if the remote unlocking distance noticeably shortens, it’s time to replace it—don’t wait until it’s completely dead and you’re stuck in a parking lot. You can find them in supermarkets or auto repair shops for just a few bucks each—choose a reliable brand to avoid leakage. Different model years of the C-Class might have slight design tweaks, but those from 2015 onward mostly use this model. It’s always good to keep a spare in the car to avoid unexpected issues. I once had a key failure on a rainy day, so now I check the battery level every six months. In short, don’t overlook small things—replace it promptly, and everything will work fine again.
