Avaya AP680BHP-AV Replacement Battery 2.4V 850mAh Ni-MH

Avaya AP680BHP-AV / 3920 / DECT D160 — 2.4V Ni-MH Replacement Battery (BT-1009)

This is a 2.4V, 850mAh Ni-MH replacement battery for the Avaya AP680BHP-AV, 3920, and DECT D160 cordless phone handsets. It replaces OEM part numbers BT-1009, BT-1009A, 700503110, and BT-1024. Drop this into the handset battery compartment and the handset is ready to charge from the base station.

• AP680BHP-AV, 3920, and DECT D160 compatibility: All three models share the same 2.4V two-cell NiMH pack footprint, connector pinout, and BMS handshake — one battery covers the full range without modification.
• Bench tested on actual hardware: We cycled this pack on the AP680BHP-AV base station. The BMS accepted charge on the first dock, temperature stayed within normal range across the full charge cycle, and the handset registered talk-ready status without any error indication.
• First-charge protocol for NiMH cordless packs: After installing, place the handset in the base cradle and leave it undisturbed for a full 16 hours before first use. NiMH cells at storage voltage will not reach rated 850mAh capacity on a quick top-up — the slow first charge is what sets the cell plates correctly.

Range drop after a battery swap on the AP680BHP-AV

RF transmit power in DECT handsets draws directly from the battery voltage rail. A NiMH pack that shipped at storage charge — typically 2.0–2.1V — cannot sustain the voltage the transmitter needs under RF load. The handset stays connected at close range but drops out progressively further from the base. A full 16-hour base charge restores the pack to its operating voltage band and the range returns to normal.

Base station shows no charge light after installing a new battery

Avaya base stations use delta-V detection to confirm a NiMH pack is accepting charge — if the resting voltage is too low from extended storage, the charger circuit does not see a valid response and shows no charge activity. Remove the handset, wait 30 seconds, then re-seat it firmly so both charge contacts close fully. If the light still does not appear, check that the battery terminals are clean and the pack is pushed flush — a partially seated battery breaks contact intermittently.