About this replacement
Asus VivoBook S14 S410U Series — 11.52V Li-ion Replacement Battery (B31N1707)
This 11.52V 3500mAh (40.32Wh) Li-ion battery replaces the B31N1707 cell in the Asus VivoBook S14, S410U, S410UA, S410UF, and over 25 additional S410 variants. It fits the three-cell configuration native to this notebook line. Install it when the original cell no longer holds a usable charge or fails to register in Windows.
- S410U series compatibility: The S410U, S410UA, and S410UF share the same 11.52V three-cell rail, connector pinout, and BMS handshake protocol — all run the B31N1707 footprint without modification to the battery bay or firmware.
- Bench tested on actual hardware: We cycled this cell through charge and full discharge on an S410UA unit. The BMS negotiated correctly with the EC firmware, charge termination triggered cleanly at 100%, and no overcurrent flags appeared during the discharge run.
- Post-install calibration on VivoBook S14: After fitting this cell, run one full discharge until the laptop hibernates at the low-voltage cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor after fitting the B31N1707 replacement
The VivoBook S14 EC reads battery health data from EEPROM registers embedded in the original cell. A new cell ships with reset EEPROM counters, so the BIOS interprets the mismatch as a degraded or unknown unit. This is a firmware artefact, not a fault with the replacement cell. Run the full discharge-to-hibernate then uninterrupted charge cycle once, and the learn cycle will overwrite the stale register values.
VivoBook S14 shutting down at 20–30% battery shown on screen
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual voltage curve. The IC is still using the old cell's discharge profile, so it underestimates remaining capacity and signals a low-voltage shutdown well before the cell is genuinely depleted. Two to three full discharge-and-charge cycles force the fuel gauge to re-map the curve against the new chemistry. After calibration, the OS percentage readout will track accurately down to the BMS cutoff voltage of approximately 9.0V.