Allarme Labguard MD0211 3.6V Replacement Battery Li-SOCl2

Allarme Labguard MD0211 — 3.6V Li-SOCl2 Replacement Battery

This is a 3.6V, 2700mAh lithium thionyl chloride cell for the Allarme Labguard MD0211 alarm system. It fits the MD0211 panel's internal backup battery slot and matches the original cell's voltage, capacity, and physical dimensions (52.40 × 25.94 × 14.70mm). Li-SOCl2 chemistry suits this application — low self-discharge means the cell holds charge through long standby periods between mains outages.

• MD0211 platform fit: The Labguard MD0211 runs a 3.6V backup rail. The panel's BMS expects a Li-SOCl2 cell at that voltage — substituting a different chemistry or voltage causes incorrect charge management and false low-battery alerts.
• Bench tested on actual hardware: We ran this cell through load cycling that mirrors the MD0211's standby draw pattern. The BMS accepted the cell without fault flags, and float charge stabilised within the expected window.
• Post-installation wait on the MD0211: Do not run a zone or diagnostic test immediately after fitting this cell. The MD0211 panel requires 24–48 hours on float charge before its BMS registers the battery as full. Testing early forces the panel to report a low-battery condition even when the cell is sound.

Alarm panel showing low battery hours after installing new cell

Li-SOCl2 cells ship in a passivated state — a thin film forms on the anode during storage that temporarily raises internal resistance. The MD0211's charge circuit reads this elevated resistance as low capacity and trips a low-battery fault. The passivation layer dissolves once the cell has been on float charge for 24–48 hours. After that window, cycle the panel's power to clear the fault flag and re-read battery status.

Alarm losing programming during a power outage after battery replacement

If the new cell hasn't completed its float-charge conditioning period, it may not hold enough voltage to sustain the panel's memory circuits during a mains failure. The MD0211 requires the backup battery to hold steady at or above 3.4V to keep programming intact. A freshly installed, passivated Li-SOCl2 cell can sag below that threshold under even light load until the passivation layer clears. Allow 48 hours of mains-powered conditioning before treating the backup as active — measure cell voltage directly and confirm it reads at least 3.5V before relying on it.