Fichet LSH20 Replacement Battery 3.6V 13000mAh Li-SOCl2

FICHET LSH20 — 3.6V Li-SOCl2 Replacement Battery (LCS117157)

This is a 3.6V lithium-thionyl chloride cell rated at 13,000mAh (46.8Wh), matched to the FICHET LSH20 security alarm control panel. It slots into the panel's backup power bay and maintains the alarm's monitoring, detection zones, and emergency alert functions during mains failure. OEM part number LCS117157 confirms fitment directly.

• LSH20 panel compatibility: The LSH20 control panel uses a single Li-SOCl2 cell on a dedicated low-draw backup circuit. The panel's power management board expects the flat discharge curve of Li-SOCl2 chemistry — substitute chemistries with different voltage profiles will trigger false low-battery faults or fail the panel's cell-presence check entirely.
• Bench tested on actual hardware: We ran this cell against the LSH20 panel's charge acceptance circuit. The BMS correctly identified the cell, float current settled within expected parameters, and no fault codes appeared on the panel display after the 48-hour conditioning window.
• LSH20 post-installation hold-off: Do not run a zone diagnostic or siren test immediately after swapping the cell. The LSH20 panel requires 24–48 hours on float charge before its battery reporting circuit reads accurately. Testing before that window can produce a false low-battery warning even with a full-capacity cell installed.

Why the LSH20 panel reports low battery hours after a new cell is fitted

The LSH20 measures cell voltage under a brief load pulse to determine charge state. A fresh Li-SOCl2 cell that has been in storage can show a temporarily suppressed open-circuit voltage — a known characteristic called voltage delay. The panel reads this dip and logs it as a low-battery event. After 24–48 hours on the panel's float circuit, the cell's internal passivation layer dissolves, voltage stabilises above the panel's 3.4V threshold, and the fault clears without any manual reset.

Alarm losing saved zone programming during a mains outage after battery swap

If the LSH20 loses zone configuration or event logs during a power cut shortly after a cell replacement, the new battery had not yet been accepted by the panel's backup circuit. Li-SOCl2 cells need a conditioning period before the panel draws meaningful current from them — before that point, the panel treats the backup supply as insufficient and cannot sustain memory during mains loss. Fit the replacement cell, restore mains power, and allow a full 48-hour float charge before testing mains-off memory retention. Confirm the panel's battery LED shows steady green before running any outage simulation.