About this replacement
Asus VivoBook Max X441SA Series — 10.8V Li-ion Replacement Battery (A31N1537)
This is a 10.8V, 2200mAh (23.76Wh) Li-ion battery replacing OEM part A31N1537 in the Asus VivoBook Max X441 series. It fits the X441SA, X441SC, X441UA, and X441UV among others. The connector, cell count, and BMS handshake match the original specification.
- X441 series compatibility: All X441 variants in this range share the same three-cell 10.8V rail, the A31N1537 connector pinout, and the same BMS communication protocol — which is why one cell fits across the SA, SC, UA, and UV chassis without modification.
- Bench tested on actual hardware: We ran this cell through charge-discharge cycles on an X441UA unit. The BMS accepted charge from zero, reported state-of-charge correctly to the OS, and held voltage above 10.4V through the full discharge curve without triggering a premature cutoff.
- Post-install calibration on the X441 series: After fitting this cell, run the laptop down to hibernate cutoff on battery only — no AC — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning the firmware throws after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
Asus BIOS on the X441 platform stores charge history and cycle count in EEPROM on the old cell. When a new cell goes in, the BIOS reads no history and flags the battery as degraded or unknown. This is a firmware state — not a fault with the replacement cell. One full discharge-to-hibernate followed by an uninterrupted charge to 100% completes the learn cycle and clears the warning. After two to three cycles the fuel gauge IC recalibrates and health reporting normalises.
Laptop shutting down at 20–30% shown on the OS gauge
This happens when the fuel gauge IC still holds calibration data from the worn original cell. The OS gauge reads 20–30% but the new cell's actual voltage under combined CPU and display load has already dropped below the BMS cutoff threshold — so the system shuts down without warning. The fix is a full recalibration cycle: discharge to automatic hibernate with no AC attached, then charge straight to 100% without interruption. Repeat twice if the shutdowns continue — by the third cycle the fuel gauge maps correctly to the new cell's voltage curve.