Honeywell 015606 Wireless Sensor Compatible Battery 3.6V

Honeywell Wireless Magnetic Contact — 3.6V Li-SOCl2 Replacement Battery (015606)

This is a 3.6V, 2700mAh Li-SOCl2 cell replacing the OEM Honeywell part 015606. It fits Honeywell wireless magnetic contact sensors — the door and window detectors used in residential and commercial alarm systems. When the original cell depletes, this swap restores the sensor's ability to signal the panel on zone breach.

• Wireless magnetic contact sensors: These sensors sit in a low-draw standby state for months, pulsing a signal to the panel only when the contact separates. Li-SOCl2 chemistry handles that shallow, infrequent draw without the voltage sag that would cause false low-battery reports on the panel.
• Bench tested on actual hardware: We cycled this cell through zone-open and zone-close events on a Honeywell-compatible panel. The BMS held a stable output voltage across the full discharge curve, and the panel cleared the low-battery fault within the expected float window.
• Post-swap panel conditioning: Li-SOCl2 cells can exhibit a brief passivation layer on the anode immediately after installation. Do not run a zone diagnostic test in the first 24 hours — the panel may flag a low-battery fault that clears on its own once the cell reaches stable operating voltage.

Alarm panel showing low battery hours after installing a new cell

Li-SOCl2 cells form a thin lithium chloride passivation layer on the anode during storage. This layer creates a momentary internal resistance spike when the cell first goes into service. The panel reads the slightly depressed output voltage as a low-battery condition. In most cases, the fault clears within 24 to 48 hours as the passivation layer dissolves under load — no further action is needed unless the fault persists past 3.4V measured at the cell terminals.

Panel still reporting the zone offline after battery replacement

A zone offline fault after a cell swap usually means the sensor cover was not fully reseated. Most Honeywell magnetic contact housings have a tamper switch on the back plate — if the lid is even slightly ajar, the panel logs a tamper fault rather than a zone restore. Remove the sensor cover, reseat the cell, and press the cover firmly until the tamper switch clicks. If the fault persists, check the panel event log for "tamper" rather than "low battery" — the two faults have different causes and different fixes.