Honeywell ExiLED22 Replacement Battery 3.6V 700mAh 290180

Honeywell ExiLED22 / ExiLED34 Series — 3.6V Ni-MH Replacement Battery (290180)

This is a 3.6V 700mAh Ni-MH cell that replaces part number 290180 in Honeywell emergency lighting units. It fits the ExiLED22, ExiLED34, MaxLED26, and ProLED series, along with three additional compatible models. The cell provides backup power to integrated LED lights during mains failure in fire alarm and emergency evacuation systems.

• ExiLED and MaxLED compatibility: These models share the same 3.6V single-cell Ni-MH platform, connector footprint, and charge management circuit. The BMS in each unit expects the same charge acceptance profile, so this cell slots in without any firmware or hardware adjustment.
• Bench tested on actual hardware: We ran this cell through a full charge cycle on a representative ExiLED unit and monitored the BMS handshake. The controller accepted the cell without fault codes, and the float charge voltage stabilised at the correct level within the expected window.
• Post-installation float charge period: Do not trigger a zone test immediately after fitting this cell. The panel needs 24–48 hours on float charge before its internal monitoring registers a full cell — running a diagnostic test before that window closes will cause the panel to report a low battery fault even though the cell is functional.

Alarm panel showing low battery hours after installing a new cell

Honeywell emergency lighting units use a supervised charge circuit that does not immediately accept a new cell as fully charged. The BMS compares terminal voltage against an internal threshold that only clears after a sustained float charge period of 24–48 hours. Fitting a fresh cell does not bypass this check — the panel is measuring charge state, not just cell presence. Leave the unit on mains power for 48 hours, then check panel status. The low battery indication should clear once the float threshold is met.

Alarm losing saved programming during a mains power outage after cell replacement

If the panel loses zone programming during a power outage shortly after a battery swap, the replacement cell had not yet been accepted by the backup circuit. A cell that has not completed its initial float charge cycle cannot sustain the panel's memory retention voltage under load. This is not a faulty cell — it is a conditioning gap. Allow 48 hours of continuous mains-connected charge before deliberately cutting mains power. The backup circuit needs to reach a minimum of 3.4V under load to hold panel memory.