Asus A31-S6 Replacement Battery 11.1V 6600mAh Li-ion

Asus S6 / S6F / S6Fm Series — 11.1V Li-ion Replacement Battery (A31-S6 / A32-S6 / A33-S6)

This is an 11.1V 6600mAh Li-ion replacement battery for the Asus S6, S6F, S6F Leather Collection, and S6Fm notebooks. It fits using OEM part numbers A31-S6, A32-S6, A33-S6, 70-NEA1B2000M, 90-NEA1B2000, 90-NEA1B3000, and 90-NEA1B1000. Capacity is 73.26Wh — matching the original cell specification.

• S6 series battery fitment: The S6, S6F, and S6Fm share the same 11.1V three-cell rail, connector pinout, and BMS handshake protocol across all trim levels including the Leather Collection variant. One battery SKU covers the full range.
• Bench tested on actual hardware: We ran this cell through charge, full discharge, and charge cycles on the S6 platform. The BMS communicated correctly with the Asus EC, charge termination triggered at the expected voltage, and no fault flags were thrown during thermal monitoring.
• Post-install calibration on the S6: After fitting this battery, run one full discharge until the laptop hibernates on its own, then charge uninterrupted to 100% without using the machine. This resets the BIOS battery learn cycle and clears the inaccurate health warning the S6 EC generates after any cell swap.

Why the S6 BIOS reports poor battery health immediately after a cell swap

The Asus S6 EC reads health data from EEPROM registers on the battery's fuel gauge IC. When you install a new cell, those registers still carry factory default values — not values calibrated to the new chemistry. The EC compares what it reads against its stored baseline and flags the battery as degraded or unknown. This is not a fault with the replacement cell. One full discharge-to-hibernate followed by an uninterrupted charge to 100% allows the EC to rewrite those registers against the actual cell capacity.

S6 shutting down abruptly while the OS still shows 20–30% charge remaining

This symptom means the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The OS gauge is reading a predicted state-of-charge, but the real cell voltage is dropping faster than expected under combined CPU and display load. When cell voltage hits the hardware cutoff threshold — around 9.0V on this 3S pack — the system shuts off regardless of what the OS reports. Run two to three full discharge-and-recharge cycles without interrupting the charge phase, and the gauge IC will recalibrate to the correct voltage cliff point.