Asus FX506IV Replacement Battery C41N1906 15.4V 5600mAh

Asus TUF Gaming FX506IV / FA706IU Series — 15.4V Li-Polymer Replacement Battery (C41N1906)

This is a 15.4V, 5600mAh (86.24Wh) Li-Polymer cell built to replace the C41N1906 battery in the Asus TUF Gaming A15 and A17 laptop lines. It fits FX506IV, FA706IU, FA506IV, and over 40 related TUF Gaming variants. The four-cell configuration matches the original voltage rail and connector pinout for these platforms.

• TUF Gaming A15 / A17 platform fit: These models share the same 15.4V four-cell architecture, BMS handshake protocol, and C41N1906 connector layout. Swapping between FA506 and FA706 variants in this family does not change the battery spec — the BMS negotiates with the same EC firmware across the range.
• Bench tested on actual hardware: We cycled this cell on an FA506IV under sustained CPU and GPU load. The BMS held the charge curve correctly, hit full 15.4V at termination, and tripped over-discharge protection at the expected low-voltage threshold without a hard shutdown event.
• Post-install calibration on TUF Gaming laptops: After fitting this cell, run the laptop from 100% down to automatic hibernate-cutoff under normal load — do not manually shut it down. Then charge uninterrupted back to 100%. This single learn cycle resets the EC's fuel gauge against the new cell and clears the inaccurate health warning the BIOS flags after every cell swap.

Why the BIOS flags poor battery health immediately after fitting a new C41N1906 cell

The TUF Gaming EC reads health data from the battery's EEPROM — a small memory chip that stores cycle count, rated capacity, and design voltage. A brand-new cell ships with factory-default EEPROM values that the EC has never seen before, so it compares them against the worn profile stored from the old battery and raises a health alert. This is a data mismatch, not a defect in the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted full charge gives the EC enough data to update its internal model. After that cycle, the health warning clears and the gauge tracks normally.

Laptop shuts down at 20–30% shown on the TUF Gaming fuel gauge

This happens when the OS fuel gauge is still calibrated to the old cell's discharge curve. Under full CPU plus GPU load — common on TUF Gaming hardware — the new cell's voltage drops faster than the uncalibrated gauge expects, and the EC triggers a low-voltage shutdown before the displayed percentage reaches zero. It is not a fault in the replacement cell. Force one complete discharge cycle to hibernate without interrupting the load. After charging back to 100%, the gauge IC recalibrates against the new cell's actual voltage-to-capacity curve and the early shutdowns stop.