About this replacement
Asus VivoBook S430UF Series — 11.55V Li-ion Replacement Battery (B31N1732)
This is a 11.55V, 3600mAh (41.58Wh) Li-ion replacement battery for the Asus VivoBook S430UF, K430UF, V430UF, and S4300UF laptops. It fits the OEM socket and connector without modification. Order by part number B31N1732 or cross-reference 0B200-02960000 and 0B200-02960400 to confirm fitment before purchasing.
- S430 / K430 / V430 platform fitment: These models share the same 11.55V three-cell architecture, battery connector pinout, and BMS handshake protocol — that is why a single part number covers the entire platform. The charge controller communicates with the same EEPROM register set across all variants.
- Bench tested on actual hardware: We ran this cell on a VivoBook S430UF under a mixed CPU and display load. The BMS held the charge curve cleanly from 0% to 100%, and the thermal protection tripped correctly above the rated cutoff threshold.
- Post-install learn cycle on the S430 platform: After installing, run one full discharge down to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that nearly always appears after a cell swap on this platform.
Why the VivoBook S430UF BIOS reports poor battery health after a new cell install
The S430UF BIOS reads health data from an EEPROM register on the battery's BMS board. When a new cell is installed, that register contains factory default values that do not match the laptop's charge history — the BIOS interprets this mismatch as a degraded battery. This is not a fault with the new cell. Running one complete discharge-to-hibernate and a full uninterrupted charge resets the learn cycle and writes fresh data into the register, clearing the warning on next boot.
S430UF shutting down at 20–30% charge shown on the fuel gauge
This happens because the fuel gauge IC is still calibrated to the old, degraded cell's voltage curve. A new cell holds voltage higher and longer, then drops steeply near depletion — the fuel gauge misreads that cliff and fires a shutdown before the percentage reaches zero. It is not a BMS fault or a compatibility issue. Run two full discharge-to-hibernate cycles followed by uninterrupted charges to 100% and the gauge IC will recalibrate to the new cell's curve, with the cutoff moving back below 5%.