About this replacement
Asus ZenBook UX331UAL-1D — 15.4V Li-Polymer Replacement Battery (C41N1715)
This is a 15.4V, 3050mAh (46.97Wh) lithium-polymer replacement battery for the Asus ZenBook UX331 series. It fits the UX331UAL-1D, UX331UN-EG080T, UX331UN-C4136R, UX331UA-EG003T, and over 113 additional UX331 variants. OEM part numbers C41N1715 and 0B200-02760000 both cross-reference to this cell.
- UX331 series fit: All UX331 variants share the same 15.4V four-cell Li-Polymer architecture, identical connector pinout, and the same BMS handshake protocol — which is why one part number covers the full lineup.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on UX331 hardware. The BMS communicated correctly with the BIOS, accepted a full charge, and the fuel gauge IC initialised without fault flags on the first cycle.
- Post-install calibration on the UX331: After fitting, run one full discharge until the laptop hibernates on its own, then charge uninterrupted to 100% without using the machine. This resets the BIOS battery learn cycle and clears the false "poor health" warning the firmware throws after every cell swap.
Why the UX331 BIOS reports poor battery health after a cell swap
The UX331 BIOS reads health data from EEPROM registers stored on the battery's internal management chip. When a new cell is installed, those registers start at factory defaults — they don't match the usage history the BIOS expects to see. The firmware interprets the mismatch as a degraded or unknown battery and flags it accordingly. One full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the learn cycle data and clears the warning.
UX331 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual discharge curve. The gauge estimates remaining capacity using data from the old cell, so its percentage readout drifts badly in the first few cycles. Under combined CPU and display load, the real voltage drops faster than the gauge predicts, and the system cuts out before the displayed percentage reaches zero. Run two to three full discharge-and-charge cycles and the fuel gauge IC will recalibrate — the shutdowns stop once the gauge tracks the actual voltage correctly.