About this replacement
Asus Zenbook Pro UX550VD / UX550VE Series — 15.4V Li-Polymer Replacement Battery (C42N1630)
This is a 15.4V, 4650mAh (71.61Wh) Li-Polymer battery for the Asus Zenbook Pro UX550VD and UX550VE series laptops. It replaces OEM part numbers C42N1630, 0B200-02520000, and C42PHCH. Fit covers over 88 UX550 variants including the BN082R, BO165T, BN120T, and BO031T.
- UX550 platform fitment: The UX550VD and UX550VE share the same 4-cell 15.4V battery architecture, connector pinout, and BMS handshake protocol. Any board revision in this series draws from the same voltage rail, so one cell SKU covers the full range without modification.
- Bench tested on actual hardware: We ran this cell on a UX550VD board and confirmed the BMS accepted the new cell without fault codes. Charge cycles completed to 100% and the protection circuit responded correctly to load spikes during CPU-intensive tasks.
- Post-install discharge cycle: After fitting, run the laptop on battery until it hibernates at the cutoff threshold, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell data and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting the C42N1630
The UX550 BIOS stores learned capacity data from the previous cell in non-volatile memory. When you swap in a new cell, that stored data no longer matches the new cell's EEPROM profile, and the firmware flags it as degraded. This is not a fault with the replacement cell — it is a calibration mismatch. Run one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100%, and the BIOS learn cycle will rewrite its stored values. After two or three cycles, the health indicator should read normal.
Zenbook Pro shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC's stored discharge curve no longer matches the actual cell chemistry — the percentage shown is based on old calibration data, not real remaining capacity. Under full CPU plus display load, the cell hits its minimum cutoff voltage before the OS gauge reaches zero, triggering an immediate shutdown. The fix is to let the laptop run down fully to hibernate-cutoff at least twice so the fuel gauge IC can map the new cell's actual voltage curve. After two calibration cycles, the shutdown threshold should align with what the screen displays, and the gauge will track accurately from around 3.5V per cell at the low end.