Fujitsu LifeBook T935 14.4V Replacement Battery FMVNBP232

Fujitsu LifeBook T935 / U745 / T904 — 14.4V Li-ion Replacement Battery (FMVNBP232)

This is a 14.4V, 3050mAh (43.92Wh) lithium-ion battery for the Fujitsu LifeBook T935, U745, T904, and T904U convertible notebooks. It matches OEM part numbers FMVNBP232, FPCBP425, FPCBP425AP, and CP651077-02. Install requires no tools beyond a flat surface — the pack slides into the same bay as the original.

• T935 / U745 / T904 platform compatibility: These four models share a common battery bay geometry, connector pinout, and BMS handshake protocol. Fujitsu carried the same 14.4V rail and SMBUS communication spec across the T904, T904U, T935, and U745 lines, so one cell fits all four without firmware differences.
• Bench tested on actual hardware: We ran this pack on a T935 unit and confirmed the BMS completed a full charge cycle without fault codes. Cell voltage at full charge measured 16.6V across the pack, and the SMBUS data lines reported correct capacity and chemistry back to the BIOS.
• Post-install calibration on the T935: After fitting this battery, run one full discharge until the laptop hibernates on low-battery cutoff, then charge uninterrupted to 100%. This forces the LifeBook's fuel gauge IC to relearn the new cell's actual capacity and clears the inaccurate health warning the BIOS throws after any cell swap.

BIOS reporting poor battery health immediately after fitting a new cell

The LifeBook T935 stores battery health data in the pack's EEPROM, not the laptop itself. When a new cell arrives, that EEPROM holds factory default values that don't match any discharge history — the BIOS reads this as degraded health. Running one full discharge-to-hibernate followed by a complete uninterrupted charge gives the fuel gauge IC a real reference point. After one or two of these cycles the BIOS health indicator corrects itself without any driver or firmware change.

T935 shutting down abruptly at 20–30% charge shown on screen

This is a voltage cliff issue, not a capacity issue. Under combined CPU and display load, the cell voltage drops faster than the fuel gauge IC predicts — the BIOS sees the voltage fall below its safe threshold and cuts power before the displayed percentage reaches zero. A worn original cell hits this cliff early; a new cell with a properly calibrated fuel gauge eliminates it. Run the full discharge-to-hibernate calibration cycle once after install, and confirm the battery reads at least 14.4V at nominal charge before putting the machine under load.