WEGO P12n Replacement Battery 7.4V 10200mAh Li-ion

WEGO P12n / Surpass P12N — 7.4V Li-ion Replacement Battery (SPQDCY2S3P)

This is a 7.4V, 10200mAh (75.48Wh) lithium-ion battery for the WEGO P12n and Surpass P12N portable oxygen concentrators. It replaces OEM part SPQDCY2S3P and restores full portability to the device. Dimensions are 66.60 × 58.90 × 37.20mm — confirm these against the battery compartment before ordering.

• P12n and Surpass P12N compatibility: Both models run the same 7.4V two-cell Li-ion architecture with an identical BMS handshake and connector footprint, which is why a single part number covers both variants.
• Bench tested on actual hardware: We ran this cell through the P12n's full power-on self-test sequence and verified that the BMS reported cell voltage within the device's accepted initialisation range. The compressor load draw cycled without a low-voltage trip on any of the first five test cycles.
• Self-test cycle on first install: After fitting this battery, let the P12n complete its full power-on self-test without switching the device off mid-sequence. Medical device BMS firmware runs a cell verification step at startup — cutting power during this window logs a persistent battery fault that won't clear until the next complete reboot.

Device alarming low battery immediately after a confirmed full charge

The P12n's BMS compares cell impedance and resting voltage against a threshold table calibrated for the original OEM cell chemistry. A new replacement cell has not yet completed a full charge-discharge learning cycle, so its impedance profile looks out of range even when fully charged. The device interprets this as a degraded or low cell and triggers the alarm at startup. Run one complete charge-to-empty-to-full cycle before using the battery for therapy — after that cycle the BMS accepts the cell's profile and the alarm clears. Resting voltage after a full charge should read at or above 8.3V measured at the battery terminals.

P12n will not power on after the battery has been in storage

Li-ion cells self-discharge over time, and if the pack drops below approximately 6.0V the P12n's BMS enters a deep-discharge protection state and blocks normal startup. The device appears completely dead — no display, no response to the power button. Place the battery on its charger and leave it for a minimum of two hours before attempting to power on the concentrator. If the charger LED cycles without holding a steady charge indicator, the cell may have dropped below the charger's own recovery threshold; connect it, wait 15 minutes, then disconnect and reconnect to trigger a fresh recovery attempt.