C41-N541 Asus Q501L Replacement Battery 14.8V 4500mAh

Asus Q501L Series — 14.8V Li-Polymer Replacement Battery (C41-N541)

This 14.8V, 4500mAh (66.6Wh) lithium-polymer battery replaces the original C41-N541 cell in the Asus Q501L notebook series. It fits the Q501L, Q501LA, Q501LA-BBI5T03, and Q501LA-BSI5T19. The four-cell Li-Polymer pack slots into the same bay as the factory unit with no modification.

• Q501L and Q501LA compatibility: All four Q501L variants share the same 14.8V power rail, C41-N541 connector pinout, and BMS handshake protocol — which is why one cell covers the full model range without firmware differences.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a Q501LA unit. The BMS negotiated correctly, protection circuits tripped at expected low-voltage thresholds, and the charge controller accepted the cell without fault codes.
• First-cycle calibration on the Q501L: After installing, run the laptop down to hibernate-cutoff on battery only, then charge uninterrupted to 100%. This forces the Q501L's fuel gauge IC to re-learn the new cell's capacity curve and clears the inaccurate health warning the BIOS throws after every cell swap.

BIOS reporting poor battery health immediately after fitting a new C41-N541

The Q501L BIOS reads health data stored in the battery's EEPROM and compares it against a learned baseline from the previous cell. A brand-new cell has a blank or mismatched EEPROM record, so the BIOS flags it as degraded before any cycling has occurred. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% overwrites the stored baseline and clears the warning. If the warning persists after two full cycles, check BIOS version — some Q501L firmware revisions require an update before they accept third-party cell EEPROM data correctly.

Q501LA shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC still holds calibration data from a degraded old cell and maps the new cell's voltage curve incorrectly. Under full CPU and display load, the actual cell voltage drops faster than the gauge predicts — the laptop hits the hardware low-voltage cutoff while the OS still shows 20–30% remaining. The fix is two or three complete discharge-to-hibernate and full-recharge cycles so the fuel gauge IC recalibrates against the new cell's actual voltage curve. After calibration, the reported percentage and the real cutoff point will align — target a resting voltage of around 16.4V at a full charge state for this four-cell pack.