About this replacement
Asus N550 Series — 15V Li-Polymer Replacement Battery (C41-N550)
This is a 15V, 4000mAh (60Wh) Li-Polymer replacement battery for the Asus N550 notebook series. It fits the N550, N550J, N550X47JV, N550X47JV-S, and over 150 additional N550 variants. Capacity and voltage match the original C41-N550 specification exactly.
- N550 series compatibility: These models share the same 15V power rail, C41-N550 connector layout, and four-cell Li-Polymer BMS handshake. Any N550 variant listed accepts this cell without hardware modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an N550J. The BMS communicated correctly with the EC, charge current tapered normally at the 4.2V-per-cell threshold, and no fault codes triggered during the test.
- First-cycle reset on N550 after swap: After fitting this battery, run the laptop down to hibernate-cutoff under normal load, then charge uninterrupted to 100%. This forces the embedded controller to complete a learn cycle against the new cell and clears the inaccurate health warning the N550 BIOS posts after every cell replacement.
Why the N550 BIOS reports poor battery health after a cell swap
The N550 embedded controller reads cycle count and state-of-health data stored in the original cell's EEPROM. When a new cell arrives with a fresh EEPROM, the EC compares those values against its stored baseline and flags a mismatch as degraded health. This is a firmware-side artefact, not a cell fault. One full discharge-to-hibernate followed by an uninterrupted charge to 100% lets the EC rebuild its learned capacity baseline against the new cell and clears the flag.
N550 shutting down at 20–30% remaining after battery replacement
The fuel gauge IC on the N550 board calibrates its state-of-charge curve against the old cell's discharge profile. With a new cell installed, the IC underestimates remaining capacity and triggers a low-voltage shutdown earlier than expected. The fix is two to three full calibration cycles: discharge to hibernate-cutoff, then charge to 100% without interruption each time. After the second or third cycle the gauge re-maps to the new cell and the premature shutdown stops. Check that the cell voltage at reported 0% reads no lower than 14.4V across the pack terminals — anything lower points to a different fault.