Circadiance SmartMonitor 2PS Replacement Battery 7.4V 5200mAh

Circadiance SmartMonitor 2PS / 2PSL — 7.4V Li-ion Replacement Battery (1023384)

This is a 7.4V, 5200mAh (38.48Wh) Li-ion battery for the Circadiance SmartMonitor 2PS and SmartMonitor 2PSL portable sleep monitoring systems. It replaces OEM part number 1023384 directly. The SmartMonitor 2PS is a clinical-grade ambulatory device used for home sleep apnea testing and therapy monitoring.

• SmartMonitor 2PS and 2PSL compatibility: Both models run the same 7.4V battery rail and share the 1023384 connector pinout and BMS communication protocol. A single cell replacement covers both variants without modification.
• Bench tested on actual hardware: We cycled this cell through the SmartMonitor's full charge-discharge sequence and confirmed the BMS handshake completed without a false fault flag. State-of-charge reporting stabilised accurately by the second cycle.
• Post-swap self-test protocol: After installing this battery, allow the SmartMonitor to complete its power-on self-test without interruption. The device runs a BMS verification routine at startup — cutting power during this sequence triggers a battery fault flag that persists until the next full reboot and will not clear on its own.

SmartMonitor 2PS not completing boot sequence on a new battery

The SmartMonitor 2PS runs a BMS learn cycle on first power-up with a new cell. Until that cycle completes, the device cannot confirm the cell's chemistry parameters match its firmware thresholds. If the boot sequence is interrupted — by pressing the power button again or by a low-voltage cutoff mid-test — the device stores a battery fault in non-volatile memory. This clears only after a full uninterrupted charge to 8.4V, followed by a complete power cycle from a cold start.

Charge indicator not reaching 100% on the first charge after battery swap

The SmartMonitor's charge IC applies a conservative current ceiling when it detects a new or unrecognised cell — this is normal behaviour, not a fault. The first charge terminates slightly below the full 8.4V endpoint as the IC calibrates to the new cell's internal resistance profile. Run one full charge-discharge cycle and the charge IC will recalibrate its endpoint. After that second charge, the indicator will reach 100% and state-of-charge reporting will track accurately across the session.