Xiaomi Mi Notebook Air 13.3 2018 Compatible Battery R13B01W 7.6V 5250mAh

Xiaomi Mi Notebook Air 13.3 2018 — 7.6V Li-Polymer Replacement Battery (R13B01W / R13B02W)

This is a 7.6V, 5250mAh (39.9Wh) lithium-polymer replacement battery for the Xiaomi Mi Notebook Air 13.3 2018 ultrabook. It replaces OEM part numbers R13B01W and R13B02W. Install it when the original cell no longer holds a usable charge or fails to power the notebook off the mains.

• Mi Notebook Air 13.3 2018 fitment: Both R13B01W and R13B02W share the same 7.6V rail, connector pinout, and BMS handshake on this 2018 chassis. Either part number pulls the same EEPROM data during charge negotiation, so the motherboard recognises this cell without a firmware workaround.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Mi Notebook Air 13.3 2018 board. The BMS negotiated correctly at 7.6V, charge current stepped down as expected at high state-of-charge, and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
• Post-install recalibration on this chassis: After fitting, run the notebook down to automatic hibernate cutoff on battery only — no charging mid-cycle — then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on this model.

BIOS reporting poor battery health immediately after fitting this cell

The Mi Notebook Air 13.3 BIOS reads health data from EEPROM stored on the battery's fuel gauge IC. When a new cell arrives, that EEPROM carries factory defaults that don't match the learned discharge curve the BIOS expects. The system flags it as degraded or unknown — not because the cell is faulty, but because the learn cycle hasn't run yet. One full discharge-to-hibernate followed by an uninterrupted charge to 100% resets the baseline and resolves the warning.

Notebook shuts down at 20–30% battery shown on screen

This happens when the fuel gauge IC still holds calibration data from the old, degraded cell. The percentage displayed doesn't match real cell voltage under combined CPU and display load. When actual cell voltage drops below the protection cutoff — typically around 6.0V under load — the notebook cuts power even though the OS shows charge remaining. Run two full discharge-to-hibernate and charge-to-100% cycles without interruption. After the second cycle, the fuel gauge IC recalibrates against the new cell's actual voltage curve and the early shutdowns stop.