Bird Avea Vent 68339 Replacement Battery 24V 4000mAh

Bird Avea Vent 68339 — 24V Ni-MH Replacement Battery

This is a 24V, 4000mAh Ni-MH replacement battery for the Bird Avea Vent 68339 portable intensive care ventilator. It powers the unit during patient transport or temporary mains-off operation. Capacity is 96Wh, matching the original cell specification.

• Avea Vent 68339 compatibility: The Avea Vent 68339 runs a 24V power rail with a BMS that monitors cell chemistry and state-of-charge at startup. This cell matches that voltage rail and Ni-MH chemistry requirement, so the BMS handshake completes at boot without triggering a battery fault.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench before shipping. The BMS accepted the cell, completed its verification pass, and the charge indicator advanced normally through all stages without fault codes.
• Power-on self-test protocol: After installing this battery, let the Avea Vent complete its full power-on self-test cycle without interruption. The device runs a BMS verification sequence at every startup — cutting power during this window registers a false battery fault that will persist until the next full reboot.

Why the Avea Vent 68339 alarms low battery after a confirmed full charge

The Avea Vent's BMS uses a learned capacity threshold to judge whether the installed cell is fit for clinical use. A new Ni-MH cell hasn't yet been through a full charge-discharge cycle, so the BMS has no reference data to confirm full capacity. Until it does, the firmware applies a conservative threshold and may flag a low battery condition even when the cell is fully charged. Run one complete charge-discharge cycle on the device before clinical deployment. After that cycle the BMS recalibrates its threshold to the actual cell capacity and the alarm clears.

Aveva Vent 68339 won't power on after the battery sat unused in storage

Ni-MH cells self-discharge over time, and if a stored cell drops below roughly 18–19V the BMS treats it as a deep-discharged or fault state and blocks power-on. The ventilator will show no response or a persistent battery fault on the screen. Connect the device to mains power first — this bypasses the battery rail and lets the charge IC begin a recovery charge at a reduced current. Once the cell recovers above the BMS recovery threshold, typically around 21V, normal charging resumes and the unit will power on from battery again.