About this replacement
Bionet Oxy9 Vet — 3.6V Ni-MH Replacement Battery (180AAH3BML)
This is a 3.6V, 1800mAh Ni-MH replacement battery for the Bionet Oxy9 Vet veterinary pulse oximeter. It fits the Oxy9 Vet directly, using OEM part numbers 180AAH3BML and OX-BAT. The Oxy9 Vet monitors oxygen saturation and pulse rate in animals during clinical procedures and field examinations.
- Oxy9 Vet platform fit: The Oxy9 Vet runs a 3.6V Ni-MH cell with a specific connector and BMS handshake tied to that chemistry. Swapping to a different voltage or chemistry causes the BMS to reject the cell outright. This battery matches that voltage rail and connector exactly.
- Bench tested on actual hardware: We ran this cell through the Oxy9 Vet's power-on sequence and charge cycle. The BMS accepted the cell, completed its internal verification, and the charge indicator advanced normally through all stages without fault flags.
- Post-swap startup procedure: After installing this battery, let the Oxy9 Vet complete its full power-on self-test without interruption. The device runs a BMS verification step at startup — cutting power during that sequence triggers a false battery fault that sticks until the next clean reboot.
Why the Oxy9 Vet won't complete its boot sequence on a new battery
The Oxy9 Vet runs a BMS learn cycle on first use. A fresh Ni-MH cell starts with an uncharacterised capacity profile, and the device's charge IC applies a conservative limit until one full charge-discharge cycle completes. If the boot sequence is interrupted — even once — the device logs a battery fault and holds it. A clean power-on followed by one uninterrupted full cycle clears this state.
Oxy9 Vet powering on normally then shutting off unexpectedly mid-procedure
This happens when a cell has self-discharged during storage and its resting voltage sits below the BMS recovery threshold — typically under 3.0V for a 3.6V Ni-MH pack. The device powers on from residual charge but the BMS trips under load before the cell fully recovers. Place the battery on charge until the indicator reaches full, then run one complete charge-discharge cycle before clinical use. After that conditioning cycle, the BMS reads the cell's true capacity and cutoff behaviour normalises.