About this replacement
Asus F301 / X401 Series — 10.8V Li-ion Replacement Battery (A31-X401)
This is a 10.8V, 4400mAh (47.52Wh) Li-ion battery for the Asus F301, F301A, F301A1, F301U, and over 100 additional X401-series notebook models. It replaces OEM part numbers A31-X401, A32-X401, A41-X401, A42-X401, and 0B110-00140100E among others. When the original cell no longer holds a charge or the laptop loses power unplugged, this cell restores mobile operation.
- X401-series platform compatibility: The F301, X401A, X401U, and related variants all share the same battery bay geometry, three-cell connector pinout, and BMS handshake protocol — which is why one cell serves the entire lineup without modification.
- Bench tested on actual hardware: We ran this cell in an F301A and confirmed the BMS initialised correctly on first insertion, the charge IC accepted a full charge cycle without fault codes, and the fuel gauge IC tracked state-of-charge without dropping out.
- First-cycle recalibration on the F301: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell's actual capacity and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
The Asus X401-series BIOS reads cycle count, rated Wh, and health status from EEPROM data stored on the battery's BMS board — not from live voltage measurements. When a new cell arrives, its EEPROM values are blank or set to factory defaults, which the BIOS interprets as an unknown or degraded pack. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% allows the BIOS learn cycle to write fresh calibration data to the fuel gauge IC. After one or two completed cycles, the health status normalises. No firmware update or driver action is needed.
Laptop shuts down at 20–30% charge shown on the F301
This symptom points to a voltage cliff — the cell voltage under combined CPU and display load drops below the BMS cutoff threshold before the fuel gauge reads zero. It usually means the fuel gauge IC has not yet calibrated its empty-point against the new cell chemistry. The fix is the same learn cycle: discharge fully to the point Windows triggers hibernate, then charge to 100% without interruption. After two full cycles the empty-point resets and the laptop will no longer cut out early; shutdown should occur below 5% indicated.