About this replacement
Asus ZenBook Duo UX481FA Series — 15.4V Li-Polymer Replacement Battery (C41N1901)
This is a 15.4V, 4500mAh (69.3Wh) Li-Polymer replacement battery for the Asus ZenBook Duo UX481FA-HJ047T and over 100 additional ZenBook Duo and ZenBook UX481 variants. The ZenBook Duo runs two active displays simultaneously, which places a higher and more constant current draw on this cell than a standard single-screen notebook. OEM part numbers covered include C41N1901, 0B200-03520000, and 0B200-03520100.
- ZenBook Duo dual-display platform: All UX481FA and UX481FL variants share the same 15.4V four-cell architecture and C41N1901 connector pinout. The ScreenPad Plus secondary display draws power continuously alongside the main panel, so the BMS on this cell is rated to handle the sustained combined load without throttling the discharge curve.
- Bench tested on actual hardware: We cycled this cell on a UX481FA unit under dual-display load. The BMS held the 15.4V rail stable through CPU burst events and did not trigger an overcurrent cutoff during ScreenPad Plus transitions from sleep to active.
- Post-install calibration on the ZenBook Duo: After fitting this cell, run one full discharge until the laptop hibernates, then charge uninterrupted to 100% without interruption. This forces the BIOS battery learn cycle to reset against the new cell's EEPROM data and clears the false "poor health" or "0% capacity" warning that commonly appears after a cell swap on this platform.
BIOS reporting poor battery health immediately after fitting the new cell
The ZenBook Duo BIOS reads health data from EEPROM on the battery controller, not from a live cell measurement. When a new cell is installed, the EEPROM data does not match the learned values from the old pack, so the BIOS flags the battery as degraded or unknown before any charge cycle has run. This is not a fault with the replacement cell. Run one full discharge to hibernate-cutoff, then a complete uninterrupted charge to 100%. After that single learn cycle, the BIOS health indicator should return to normal on the next boot.
Laptop shuts down abruptly at 20–30% charge shown on the ZenBook Duo
This happens when the fuel gauge IC has not yet calibrated its discharge curve against the new cell's actual chemistry. The IC predicts remaining capacity using data from the previous cell, and the estimate diverges sharply under the dual-display load this platform sustains. The cell voltage drops below the BMS cutoff threshold before the gauge reaches 0%, which causes an immediate shutdown rather than a graceful hibernate. Complete two to three full discharge-and-recharge cycles — the fuel gauge recalibrates progressively and the shutdowns stop once it tracks the new cell's voltage curve accurately down to its 3.0V per-cell floor.