About this replacement
Asus Zenbook 14 UX435EG Series — 11.61V Li-Polymer Replacement Battery (C31N1914)
This is a 11.61V, 5200mAh (60.37Wh) Li-Polymer battery for the Asus Zenbook 14 UX435EG-AI084T and a wide range of UX435 and UM425 variants. It replaces OEM part numbers C31N1914, 0B200-03730100, and 3ICP6/70/81. If the original cell has degraded, swollen, or stopped holding charge, this is the direct replacement cell for that platform.
- UX435 and UM425 platform fit: These Zenbook 14 variants share the same three-cell Li-Polymer configuration, 11.61V nominal rail, and BMS connector pinout. The battery management system on all covered models uses the same EEPROM handshake protocol, so the replacement cell communicates correctly with the EC firmware without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a UX435 platform. The BMS accepted the cell without fault flags, the EC reported capacity within expected range after calibration cycles, and charge termination triggered correctly at full voltage.
- Post-installation learn cycle: After fitting, run one full discharge down to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the first boot after any cell swap on this platform.
BIOS reporting battery health as poor immediately after installation
The Zenbook 14 EC reads health data from the EEPROM of the previous cell and compares it against the new one on first boot. A fresh cell has no discharge history in its EEPROM, so the BIOS flags it as degraded — this is a data mismatch, not a fault with the replacement. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% writes a new baseline to the EC. After two to three full cycles, the health indicator normalises.
Zenbook 14 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The old calibration data predicts a voltage floor that the new cell hits earlier under combined CPU and display load, triggering a shutdown before the displayed percentage reaches zero. It is not a fault in the replacement cell — it is a mismatch between the stored discharge curve and the new chemistry's real behaviour. Run two full discharge-to-hibernate and full recharge cycles; the fuel gauge IC recalibrates and the shutdowns stop.