Honeywell AG6/WB Replacement Battery 6V 230mAh Ni-MH

Honeywell AG6/WB Series — 6V Ni-MH Replacement Battery (GP320BVH5A6)

This is a 6V, 230mAh Ni-MH rechargeable cell for Honeywell alarm panels and detectors. It fits the AG6/WB, HWAG6S, RESON8, and ADE RESON8 models, among others. It replaces OEM part numbers GP320BVH5A6, GP250BVH5A6, and CP300H.

• AG6/WB and HWAG6S platform fit: These models share the same 6V backup rail, connector pitch, and charge management circuit. A single cell spec covers the whole group — the panel draws trickle charge at the same float voltage across all variants.
• Bench tested on actual hardware: We ran this cell through charge acceptance and float stabilisation on the AG6/WB platform. The BMS accepted the cell without fault, held float charge correctly, and cleared the low-battery flag after the conditioning period.
• Post-install conditioning on Honeywell panels: Do not trigger a zone test immediately after swapping this cell. The panel needs 24–48 hours on mains power to bring the new cell to full float charge. Running a test before that window closes will almost always trigger a false low-battery warning.

Alarm panel showing low battery hours after installing a new cell

Honeywell AG6/WB panels check battery voltage against a threshold that assumes a fully conditioned cell. A fresh Ni-MH cell straight from storage sits below that threshold until the panel's trickle charger brings it up to float — typically 6.0–6.5V under load. The panel is not faulty and the new cell is not defective. Leave the panel on mains power for 48 hours and the low-battery fault will clear automatically.

Siren not sounding during a test cycle after backup battery replacement

The AG6/WB siren output is tied to backup battery state during self-test. If the panel has flagged the battery as low — even a false flag during the conditioning window — it suppresses the siren trigger as a precaution. This is a firmware-level safety hold, not a wiring fault. Wait until the low-battery fault clears, then rerun the test; the siren should activate normally once the cell reaches full float at approximately 6.0V.