Nellcor Bedside SpO2 X1 Compatible Battery 10.8V 4400mAh

Nellcor Bedside SPO2 X 1 / Bedside SpO Patient Monitoring — 10.8V Li-ion Replacement Battery

This is a 10.8V 4400mAh (47.52Wh) lithium-ion battery for the Nellcor Bedside SPO2 X 1 and Bedside SpO Patient Monitoring units. These are continuous bedside pulse oximeters used in clinical settings to monitor patient oxygen saturation. Voltage, cell count, and connector match the original battery bay on these monitors.

• Bedside SPO2 X 1 and Bedside SpO Patient Monitoring compatibility: Both monitors share the same 10.8V three-cell Li-ion architecture, battery bay connector, and BMS communication protocol — which is why a single replacement cell pack covers both fit models without hardware modification.
• Bench tested on actual hardware: We cycled this battery through a full charge-discharge sequence and confirmed the BMS reported correct state-of-charge, passed the device's power-on self-test, and held stable voltage under the monitor's continuous SpO2 sampling load.
• Post-installation self-test protocol: After fitting this battery, let the monitor complete its full power-on self-test without interruption. The device runs a BMS verification routine at startup. Interrupting this sequence — even once — logs a battery fault that persists until the next clean reboot cycle.

Medical device alarming low battery with a freshly charged replacement installed

The Nellcor monitor's charge IC applies a conservative acceptance threshold tuned to the original cell's charge history. A new cell with no cycle history can report a state-of-charge that sits just below the device's alarm threshold, even after a full charge. This is a BMS calibration issue, not a faulty cell. Run one complete charge-discharge cycle before placing the unit back into clinical rotation — after that cycle, the reported charge level aligns correctly and the alarm clears.

Monitor will not power on after battery sat in storage

Li-ion cells self-discharge during storage. If a replacement battery has been sitting long enough, its resting voltage can fall below the monitor's BMS recovery threshold — typically around 9V for a 10.8V three-cell pack — and the device will not boot at all. Connect the monitor to mains power first and allow the charge circuit to bring the cell voltage back above the recovery threshold before attempting to boot on battery alone. Once the charge indicator shows at least two bars, a normal boot sequence should proceed.