Honeywell BW Icon + 4 Replacement Battery M05-3001-000 3.7V

Honeywell BW Icon+ Series — 3.7V Li-Polymer Replacement Battery (M05-3001-000)

This 3.7V, 1200mAh Li-Polymer battery replaces part number M05-3001-000 in the Honeywell BW Icon+ 4 Gas Detector. It fits the Icon+, Flex, and Icon models used for simultaneous H2S, CO, O2, and LEL detection. At 66.20 x 51.10 x 12.20mm, it seats directly into the existing battery bay without modification.

• Icon+, Flex, and Icon compatibility: All three models share the same 3.7V power rail, M05-3001-000 connector footprint, and BMS handshake protocol. Swapping across models in this family works without firmware conflict or charge-circuit mismatch.
• Bench tested on actual hardware: We ran this pack through full charge-discharge cycles on the BW Icon+ platform, monitoring BMS response during the four-sensor initialisation sequence. The pack held voltage without triggering a low-battery cutoff at sensor start-up.
• Post-install calibration cycle: After fitting this battery, run a full calibration cycle through the instrument menu before field deployment. The Icon+ maps battery state during calibration — skipping this step causes premature low-battery warnings during your first monitoring session in the field.

BMS lockout after the BW Icon+ sat unused in a carry case for months

Li-Polymer cells self-discharge slowly in storage. If the pack voltage drops below approximately 2.5V per cell, the BMS enters a protective lockout state and the instrument will not respond to the power button. A standard charger may also refuse to initiate a charge cycle because it reads the pack as faulted. To recover, connect the instrument to its dock charger and leave it for 30–60 minutes without pressing anything — the charger's trickle-charge stage brings the cell back above the BMS recovery threshold before the main charge cycle begins.

Voltage dropout mid-session causing sensor readings to reset or freeze

The BW Icon+ runs four electrochemical sensors simultaneously, and sustained load across all channels draws more current than any single-sensor device. If the cell is partially depleted, this sustained draw can pull bus voltage below the instrument's operational floor, triggering a mid-session reset without a low-battery warning first. This is not a firmware fault — it is a cell capacity issue. Confirm the pack is charging fully to 4.2V at the terminal before each shift to avoid this during active monitoring.