Besam PSMB-5 Electronic Door Lock Replacement Battery 12V 1500mAh

Besam PSMB-5 — 12V Ni-MH Replacement Battery (654745)

This is a 12V 1500mAh Ni-MH battery for the Besam PSMB-5 automatic door lock system. It fits commercial and institutional electronic door lock units that use OEM part number 654745 or 120589. When the original battery loses capacity, access control stops functioning — this is the direct replacement.

• PSMB-5 platform fit: The PSMB-5 control board runs a 12V supply rail and uses a specific BMS handshake to confirm battery state before enabling the lock motor. A battery at the wrong voltage or cell count will not pass that handshake — this unit matches the 12V Ni-MH cell configuration the controller expects.
• Bench tested on actual hardware: We cycled this battery through the PSMB-5 lock controller and confirmed the BMS accepted the pack, the lock motor engaged at full torque, and the low-battery warning cleared after the first charge cycle completed.
• Post-swap initialisation on PSMB-5: After fitting this battery, let the controller complete its power-up sequence before testing access credentials — the PSMB-5 runs a self-check routine on first power that takes several seconds, and interrupting it before it finishes can cause the lock to reject valid codes.

Why the PSMB-5 lock motor runs slow after a battery swap

Ni-MH cells ship in a partial state of charge — typically 40–60% of rated capacity. The PSMB-5 motor draws a sharp current spike on each lock or unlock cycle. A partially charged Ni-MH pack sags under that load, causing the motor to run slowly or stall mid-throw. Charge the replacement battery fully on the PSMB-5 controller before putting the door back into service. After the first full charge, the motor should return to full-speed operation.

Low-battery warning still showing after fitting a new battery

The PSMB-5 controller stores the last battery state in non-volatile memory. If power is restored before the controller clears that flag, the warning persists even with a new pack installed. Remove the battery, wait 20 seconds for the capacitors to discharge fully, then reinsert it — this forces the controller to re-read battery state from scratch. If the warning reappears after a full charge cycle, verify cell voltage sits at or above 13.2V under no-load conditions.