About this replacement
Taema Osiris 2 — 9.6V Ni-MH Replacement Battery (KY50900)
This is a 9.6V, 2000mAh Ni-MH replacement battery for the Taema Osiris 2 portable oxygen concentrator. It fits both the Osiris 2 and Ventilator Osiris 2 variants. The battery provides backup power to maintain oxygen delivery during power interruptions or when operating away from mains supply.
- Osiris 2 and Ventilator Osiris 2 compatibility: Both models share the same 9.6V battery rail, connector pinout, and BMS handshake protocol. One replacement covers either unit without modification.
- Bench tested on actual hardware: We cycled this cell through the Osiris 2 charge-discharge sequence and confirmed the BMS completed its self-test without fault codes. Charge acceptance and cutoff voltage matched OEM parameters on cells that had completed at least one full conditioning cycle.
- Post-installation self-test procedure: After fitting this battery, allow the Osiris 2 to complete its full power-on self-test without interrupting the boot sequence. The BMS runs a chemistry verification at startup — cutting power during this window logs a false battery fault that persists until the next clean reboot.
Low battery alarm firing immediately after a confirmed full charge
The Osiris 2 BMS sets its alarm threshold against the charge profile it expects from a conditioned OEM cell. A new Ni-MH cell has a slightly different internal resistance signature on the first two to three cycles. The BMS reads this as a marginal state-of-charge and triggers the low battery alarm even when the cell is fully charged. Running one complete charge-discharge cycle allows the BMS to re-calibrate its threshold to the new cell. After that first conditioning cycle, the alarm behaviour returns to normal.
Osiris 2 failing to power on after a battery stored outside the device
Ni-MH chemistry self-discharges at roughly 1–2% per day at room temperature. A cell stored for several months can drop below the BMS recovery threshold — typically around 7.5V for a 9.6V Ni-MH pack — and the device will not boot. Place the battery on a compatible Ni-MH charger and confirm it accepts a charge before reinstalling. Once the cell recovers above the recovery threshold, the Osiris 2 will complete its boot sequence normally. Do not attempt clinical use until the device has completed a full uninterrupted self-test cycle post-charge.