About this replacement
Amadeo A-Lock ST48 — 6V Alkaline Replacement Battery (ST48.BP.02)
This is a 6V 1200mAh alkaline replacement battery for the Amadeo A-Lock ST48 electronic door lock. It directly replaces part number ST48.BP.02 and powers the lock's keypad, motor, and Bluetooth module. When the existing battery depletes, access control stops functioning — this battery restores full operation.
- A-Lock ST48 fit: The ST48 draws power across its keypad controller, deadbolt motor, and wireless module simultaneously. This battery matches the 6V voltage rail and physical footprint (45.30 x 41.30 x 12.00mm) the lock expects — a mismatch in either causes the control board to reject the power source outright.
- Bench tested on actual hardware: We ran this battery through full lock and unlock cycles on the ST48 platform, including keypad entry and Bluetooth unlock. The BMS handshake completed cleanly and no low-battery warnings triggered immediately after installation.
- Post-swap access testing: After fitting this battery, test every access method — keypad, Bluetooth, and any registered keycards — before closing the door. The ST48 runs a firmware handshake after power interruption, and some access credentials won't be accepted until that sequence finishes.
Why the A-Lock ST48 beeps or shows low battery immediately after a fresh install
The ST48 reads voltage at startup and compares it against an internal threshold. Alkaline batteries that have been stored for extended periods can sit below that threshold even before any load is applied. Carbon-zinc or off-brand alkaline cells are especially prone to this — their open-circuit voltage often reads closer to 5.6V rather than the expected 6V. If this happens, confirm the replacement battery is fresh stock and polarity is correctly seated before assuming a fault with the lock itself.
Bluetooth won't reconnect to the ST48 after battery replacement
The ST48's Bluetooth module loses its active pairing session whenever power is fully interrupted — this is normal behaviour, not a fault. After fitting a new battery, the lock's wireless stack reinitialises, and the paired app or device needs to re-establish the connection. Open the lock's companion app, navigate to the device list, and trigger a reconnect or re-pair. If the lock doesn't appear, remove and reinsert the battery once to force a full BMS reinitialisation cycle.