About this replacement
Asus UX50 Series — 14.8V Li-ion Replacement Battery (C41-UX50)
This is a 14.8V, 2800mAh (41.44Wh) lithium-ion cell built to replace the original battery in the Asus UX50 and UX50V ultraportable laptops. It fits the UX50, UX50V, UX50V-RX05, and UX50V-XX004C variants. The OEM part numbers are C41-UX50 and P0AC001.
- UX50 and UX50V platform compatibility: These models share the same 14.8V four-cell lithium-ion configuration, identical connector pinout, and the same BMS communication protocol — which is why one cell covers the entire UX50 line without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a UX50V unit. The BMS handshook correctly, charge acceptance reached the full 41.44Wh, and the protection circuit triggered cleanly at the low-voltage cutoff threshold.
- Post-install calibration on the UX50V: After fitting this cell, run one full discharge down to hibernate cutoff — do not interrupt it — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears immediately after any cell swap on the UX50 platform.
Why the UX50 reports poor battery health right after a new cell is installed
The UX50's BIOS reads health data stored in the battery's EEPROM. When a new cell arrives, that EEPROM data does not yet match the actual charge history of the replacement, so the system flags it as degraded. This is not a fault with the cell itself. Running the battery learn cycle — one full discharge to hibernate cutoff, followed by a full uninterrupted charge — writes fresh calibration data and clears the warning. After two or three full cycles the BIOS health reading stabilises.
Fuel gauge reading wildly inaccurate for the first few charges
The fuel gauge IC on the UX50 motherboard estimates remaining capacity by comparing voltage curves against data built up over past cycles. With a new cell, that reference data is stale and the percentage shown can jump or drop by 20–30 points mid-session. This is not a defective battery — it is the IC recalibrating against the new cell's actual discharge curve. Complete two to three full discharge-to-hibernate and charge-to-100% cycles without interruption. By the third cycle the gauge typically settles within a few percentage points of actual remaining charge.