Fisher & Paykel Airvo 2 Replacement Battery 14.4V 6400mAh

Fisher & Paykel Airvo 2 / Airvo 3 — 14.4V Li-ion Replacement Battery (900PT957L)

This 14.4V, 6400mAh (92.16Wh) Li-ion battery replaces part number 900PT957L in the Fisher & Paykel Airvo 2 and Airvo 3 heated humidification systems. It provides portable power during patient transport or temporary relocation away from a wall outlet. The cell chemistry and BMS communication match the OEM specification so the device continues delivering warmed, humidified therapy without interruption.

• Airvo 2 and Airvo 3 shared battery platform: Both units use the same 14.4V rail, identical connector keying, and the same BMS handshake protocol — which is why a single part number covers both. The heater plate and flow generator draw from this shared rail, so the pack must authenticate correctly or the device will not start the heating cycle.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the Airvo 2 platform, monitoring BMS state-of-charge reporting and heater-plate draw. The BMS held the authentication handshake throughout and did not trip under the combined heater and blower load at startup.
• Transport cycle care: If the Airvo is being moved between ward locations, let the device complete its full warm-up cycle on AC power before switching to battery — the heater plate draws peak current in the first two minutes of operation, and starting that cycle cold on battery alone puts the heaviest possible load on the pack at the moment of highest inrush.

Why the Airvo 2 refuses to start the heating cycle on a new battery

The Airvo 2 runs a BMS authentication check before it powers the heater plate. If the pack voltage sits below roughly 12.8V — common after storage — the device reads the pack as insufficiently charged and blocks the heating cycle entirely. This is not a fault with the device or the battery; it is a deliberate safety threshold. Connect the Airvo to AC power, allow the battery to charge to at least 13.5V through the device's own charger circuit, then attempt transport mode. The heating cycle will initialise normally once the BMS reports a valid state of charge.

Battery percentage dropping sharply then recovering mid-transport

This happens when the heater plate cycles on after a brief flow interruption — the sudden current draw causes a momentary voltage sag that the state-of-charge indicator reads as a large capacity drop. Once the load stabilises, voltage recovers and the percentage jumps back up. It is not cell failure; it is the indicator recalibrating to a new load point. If the drop is persistent rather than momentary, check that the battery contacts on the device are clean and making full contact — oxidised pins increase resistance and amplify the sag under load.