The VL2020 is a 3 volt rechargeable vanadium-lithium coin cell, 20 mm by 2 mm, holding about 20 mAh. It is famous as the BMW key fob battery of the E-series era, recharged by induction whenever the key sat in the ignition slot.
VL2020, face and side profile, drawn to scale: 20 mm across, 2 mm thick.
Voltage
3 V
Size (D×H)
20 × 2 mm
Chemistry
Vanadium pentoxide lithium rechargeable (3 V)
Capacity
20 mAh (rechargeable)
Compatible replacements
ML2020: Manganese-lithium rechargeable in the same case; similar role, different charge profile.
Buying and replacement notes
BMW never intended these fobs to be user-serviced, so the VL2020 is welded in with angled solder tabs, commonly at 90 or 180 degrees depending on the fob revision. Replacement cells with matching tabs are widely sold, and the repair needs basic soldering plus care opening the fob shell. Aftermarket kits solve the classic complaint of a fob that only works for a day after riding in the ignition.
Commonly used in
BMW key fobs (E-series era)self-charging remotesbackup circuits
⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.
Frequently asked questions
Why does my old BMW key only work right after driving?
Its VL2020 has aged and holds almost no charge, so the ignition slot's induction charging keeps it barely alive during the drive. Replacing the cell with a new tabbed VL2020 restores normal weeks-long operation. It is a solder-in repair with plentiful guides.
Which tab angle do I need for a BMW fob?
Depends on the fob revision: both 90 degree and 180 degree tab layouts exist. Open the fob and match the old cell's tab orientation before ordering, or buy a kit specifying your exact key type. Wrong-angle tabs will not reach the pads.
Can I fit a CR2032 in a BMW diamond key?
No. Beyond the thickness difference, the fob charges its battery inductively, and charging a primary CR2032 is a rupture risk. The correct part is the rechargeable VL2020 with solder tabs; kits cost little and include the right cell.