Taema T75 Oxygen Concentrator Replacement Battery 24V 9000mAh

Taema Monnal T75 — 24V Ni-MH Replacement Battery (KY633301-ST070183A)

This 24V, 9000mAh (216Wh) Ni-MH battery replaces the OEM pack in the Taema Monnal T75 portable oxygen concentrator. It fits the T75, Monnal T75, and Air Liquide Monnal T75 variants. Cross-references KY633301-ST070183A, RC4500A4OAB, and 110588-U.

• T75, Monnal T75, and Air Liquide Monnal T75 compatibility: All three model designations share the same 24V power rail, battery connector, and BMS handshake protocol. The physical pack dimensions (147.90 × 92.00 × 67.70mm) and cell chemistry must match — Ni-MH cells sustain the flat discharge curve the T75 power management circuit expects across its oxygen delivery load profile.
• Bench tested on actual hardware: We ran this pack through the T75's power-on self-test sequence and monitored BMS communication throughout charge and discharge cycles. The BMS accepted the pack without fault codes after one full conditioning cycle. Cell voltage balance across the Ni-MH string held within tolerance under simulated concentrator load.
• Post-installation self-test cycle: After fitting this battery, allow the T75 to complete its power-on self-test without interruption. The device runs a BMS verification step at startup — cutting power during this sequence triggers a false battery fault flag that persists until the next full reboot. Do not disconnect or press standby during the first 90 seconds after power-on.

Why the Monnal T75 alarms low battery immediately after a confirmed full charge

The T75 BMS stores a charge threshold calibrated to the OEM cell's internal resistance profile. A new replacement pack has a slightly different impedance signature until it completes one full charge-discharge cycle. The BMS interprets this mismatch as insufficient charge and triggers the low battery alarm even when the pack is at full capacity. Run one complete charge and discharge before clinical use — the BMS recalibrates its threshold on the second charge and the alarm clears.

Monnal T75 not powering on after the battery sat unused in storage

Ni-MH cells self-discharge at roughly 1–2% per day. A pack stored for several months can drop below the T75's BMS recovery threshold — typically around 20V for a 24V Ni-MH string — at which point the BMS locks out the discharge circuit to protect the cells. Placing the battery on a compatible Ni-MH charger for a full charge cycle before installing it in the device is the correct first step. If the charger also refuses to start, the cells may require a slow recovery charge at 0.1C to bring individual cell voltage back above the BMS acceptance floor of approximately 1.0V per cell before the main charge cycle will initiate.