About this replacement
Dorma XS-Pro-Zylinder — 3V Li-MnO2 Replacement Battery (50111201)
This 3V lithium-manganese dioxide cell at 1600mAh (4.8Wh) is the direct replacement for the Dorma XS-Pro-Zylinder electronic lock cylinder. It also fits the DOM ELS Pro, ENiQ, and Guardian series, along with ten additional compatible models. The Li-MnO2 chemistry matches the voltage and discharge profile the motorised locking mechanism expects.
- XS-Pro-Zylinder and DOM ELS Pro platform fit: These cylinders share the same 3V single-cell architecture and connector footprint. The BMS in each reads cell voltage on insertion — a Li-MnO2 cell at nominal 3V clears the threshold immediately, whereas alkaline or NiMH substitutes do not and will trigger a low-battery alert even when fresh.
- Bench tested on actual hardware: We cycled this cell through the motorised bolt throw sequence on the XS-Pro-Zylinder. The BMS handshake completed without error codes, and the motor drew current within the expected range across repeated lock and unlock cycles.
- Post-swap access verification: After fitting this battery, test every access method — keypad, keycard, and Bluetooth app — before closing the door. Some XS-Pro-Zylinder units run a firmware handshake after power interruption that must complete fully before all credential types are accepted again.
Why the XS-Pro-Zylinder rejects a new battery as low-charge
The Dorma XS-Pro-Zylinder measures open-circuit voltage on insertion to decide whether to accept or flag a cell. Li-MnO2 cells sit at approximately 3.0V fresh off the shelf, which clears the acceptance threshold. Cells that have been stored incorrectly — warm environments above 25°C for extended periods — can drop to 2.85V or below before installation, which the BMS reads as depleted. If the cylinder immediately signals low battery with a new cell, check the cell's open-circuit voltage with a multimeter. A healthy cell reads 3.0–3.3V; anything under 2.9V should be replaced before installation.
Bluetooth app not connecting after battery replacement
A power interruption during battery swap can cause the XS-Pro-Zylinder's radio module to drop its pairing state. The lock may show as online in the app but refuse commands, or fail to appear entirely. Remove the battery, wait ten seconds for the capacitors to discharge fully, then reinsert — this forces the module to reinitialise from a clean boot. If the app still cannot connect after reinsertion, follow the re-pair sequence in the Dorma Access app, which re-establishes the Bluetooth bond without wiping stored user credentials.