Panasonic VL2020 Rechargeable Battery for BMW Slot Keys

The Panasonic VL2020 is a 3 V rechargeable lithium-ion coin cell battery designed specifically for BMW slot key fobs (also known as "diamond" or smart keys). It’s often labeled ML2020 and features solder tabs for secure installation within the key housing.

• Battery Type: Panasonic VL2020 (sometimes listed as ML2020), lithium-ion chemistry, 20 mAh capacity, 3 V nominal voltage.
• Physical Specs: Approximately 20 mm in diameter and 2 mm thick, with solder-on tabs (commonly 90° orientation; 180° variants exist too).
• Compatibility: Used in BMW models including E46, E39, E60, E90, E92 (early-2000s onwards), and others that utilize slot or diamond style key fobs.
• Installation Notes: Requires low-heat soldering to preserve battery integrity. Avoid excessive heat when replacing—many locksmiths recommend using a short wire extension instead of soldering directly to the tab to reduce risk of damage.

As a rechargeable option, the VL2020 allows repeated charging via the key’s internal circuitry or BMW charging cradle, offering a cost-effective and eco-friendly alternative to standard disposable coin cells.