About this replacement
Dolphin medical Pulse Oximeter 2150 — 4.8V Ni-MH Replacement Battery (110 322.00)
This is a 4.8V, 1700mAh Ni-MH replacement battery for the Dolphin medical Pulse Oximeter 2150. It slots into the portable monitor used to measure blood oxygen saturation and pulse rate at the bedside or in clinical settings. Voltage and cell chemistry match the original specification (OEM part 110 322.00).
- Pulse Oximeter 2150 fit: The 2150 runs a fixed 4.8V battery rail. The BMS expects Ni-MH cell behaviour — specifically the voltage curve and thermal profile that Ni-MH produces under light clinical load. Swapping to a different chemistry trips a false fault. This cell matches that profile exactly.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on a 4.8V Ni-MH test rig, logging cell voltage at each stage. The BMS accepted the cell without fault flags, and the charge IC reached full capacity without truncating the charge cycle early.
- Post-swap self-test protocol: After installation, let the device complete its full power-on self-test without interruption. The 2150 runs a BMS verification routine at startup. Cutting power mid-sequence stores a battery fault that persists until the next complete reboot — it is not a cell defect.
Why the Pulse Oximeter 2150 alarms low battery immediately after a confirmed full charge
The 2150's BMS stores a learned capacity model from the previous cell. When a new cell is installed, the BMS compares the new cell's voltage ramp against that stored model. On cycle one, a fresh Ni-MH cell has a slightly different internal resistance profile, which the BMS reads as insufficient capacity. Run one full charge-discharge cycle to let the BMS update its reference. The alarm clears on its own once the learned model matches the new cell.
Device not powering on after replacement battery sat in storage
Ni-MH cells self-discharge at roughly 1–2% per day. A cell stored for several months can drop below 3.6V total — the threshold at which the 2150's BMS refuses to initiate a boot sequence as a protection measure. Place the battery on charge for a full uninterrupted cycle before inserting it into the device. If the charger shows a fault rather than charging, the cell voltage is likely below the charger's recovery floor — check that the charger reads at least 1.0V per cell (4.0V total) before the charge IC will engage.