About this replacement
Asus ZenBook Pro 15 UX550GD — 15.4V Li-Polymer Replacement Battery (C41N1728)
This is a 15.4V, 4400mAh (67.76Wh) Li-Polymer replacement battery for the Asus ZenBook Pro 15 series. It fits the UX550GD, UX550VE, and 5500VE variants, along with over 127 confirmed models in the ZenBook Pro 15 family. OEM part numbers covered include C41N1728, C42N1728, and 0B200-02520100.
- ZenBook Pro 15 UX550 platform fit: The UX550GD and UX550VE share the same 15.4V four-cell Li-Polymer architecture, physical connector, and BMS handshake protocol. One cell covers the entire platform because the BMS negotiation sequence and pin layout are identical across these variants.
- Bench tested on actual hardware: We ran this cell on a UX550GD under sustained CPU and discrete GPU load. The BMS held charge acceptance without interruption and protection circuitry responded correctly to overvoltage and thermal thresholds throughout the test cycle.
- Post-install calibration on the ZenBook Pro 15: After fitting, run the laptop down to hibernate cutoff under normal use, then charge uninterrupted to 100% without interruption. This completes the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the ZenBook Pro 15 shuts down at 20–30% shown after a battery swap
The ZenBook Pro 15's fuel gauge IC builds a voltage-to-capacity map using data stored on the old cell's EEPROM. When a new cell is fitted, that map no longer matches the actual voltage curve of the replacement chemistry. Under full CPU plus display load, the new cell hits its low-voltage cliff before the gauge reaches 0%, so the laptop shuts down abruptly. Running two full discharge-to-hibernate and charge-to-100% cycles forces the fuel gauge IC to recalibrate against the new cell's actual discharge curve. After calibration, shutdowns at partial charge will stop.
BIOS reporting battery health as "poor" or "replace" immediately after installation
The Asus BIOS reads health status from EEPROM data written by the original cell's charge controller — data the new cell does not carry. The result is a "Battery Health: Poor" or "Replace Battery" flag that appears in MyASUS or the BIOS screen even though the replacement cell is fully functional. This is not a fault with the new cell. Run the BIOS battery learn cycle: discharge fully to automatic hibernate, then charge uninterrupted to 100%, and allow the laptop to sit at full charge for 10 minutes before unplugging. The flag clears on the next boot once the BIOS has written fresh health data at 100% state of charge.