Xiaomi Pro X 14 Replacement Battery R14B05W 15.4V 3600mAh

Xiaomi Pro X 14 — 15.4V Li-Polymer Replacement Battery (R14B05W)

This is a 15.4V, 3600mAh (55.44Wh) Li-Polymer battery for the Xiaomi Mi Notebook Pro X 14. It replaces OEM part R14B05W and fits the 14-inch laptop directly. Use it when the original cell no longer holds a charge or the system reports degraded battery health.

• Pro X 14 fitment: The Pro X 14 uses a slim Li-Polymer pack with a specific connector orientation and BMS handshake tied to the R14B05W profile. This replacement matches that voltage rail and physical footprint — 279 × 76 × 8.50mm — so the connector seats correctly and the BIOS recognises the cell.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Pro X 14 platform. The BMS accepted the new cell without error, the charge controller stepped through its full profile, and voltage held steady under combined CPU and display load.
• First-cycle calibration on the Pro X 14: After fitting, run the battery down to hibernate-cutoff — do not force shutdown — then charge uninterrupted to 100%. This gives the fuel gauge IC a full sweep against the new cell and clears the inaccurate health warning the BIOS posts after every cell swap.

BIOS reporting battery health as poor immediately after fitting the R14B05W

The Pro X 14 BIOS reads health data from the old cell's EEPROM and compares it against the new cell's charge state at first boot. A freshly fitted cell with no cycle history looks wrong to the firmware, so it flags health as poor or unknown. This is not a fault with the replacement cell. Run one full discharge-to-hibernate then a full uninterrupted charge — the BIOS battery learn cycle rewrites the health estimate against real measured data and the warning clears.

Laptop shutting down at 20–30% shown on the Pro X 14 gauge

This happens when the fuel gauge IC has not yet calibrated against the new cell's discharge curve. The IC inherited capacity data from the old degraded cell, so it maps voltage to percentage incorrectly and calls shutdown too early. Under full CPU plus display load, the cell hits a voltage cliff that the uncalibrated gauge did not predict. Run two full discharge-to-hibernate and full charge cycles — by the third cycle the gauge IC has enough data to track the new cell accurately and the early shutdowns stop.