About this replacement
Fujitsu FMV-716NU3/B Series — 10.8V Li-ion Replacement Battery (FPCBP42)
This is a 10.8V, 3400mAh (36.72Wh) Li-ion replacement battery for the Fujitsu FMV-716NU3/B and related FMV-BIBLO NB-series notebooks. It replaces OEM part numbers FPCBP42, 0643970, and FM-33. The battery slots into any chassis that accepts the original FPCBP42 cell pack.
- FMV-BIBLO NB and FMV-7xx series compatibility: These models share the same 10.8V three-cell rail, identical connector pitch, and the same BMS handshake protocol — which is why one cell pack covers all of them without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a FMV-BIBLO NB-series unit. The BMS communicated correctly with the BIOS, reported accurate state-of-charge, and held the rated voltage without tripping thermal cutoff.
- Post-install calibration on FMV LifeBook units: After fitting this battery, run one full discharge to hibernate-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 these Fujitsu models.
Why the FMV-716NU3/B BIOS reports poor battery health after a cell swap
The FMV LifeBook BIOS stores charge history and health data tied to the old cell's EEPROM signature. When a new cell installs, that stored data no longer matches the actual chemistry, so the BIOS flags it as degraded. This is not a fault with the replacement cell — it is a calibration mismatch. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% gives the BIOS enough data to rewrite its health record. After one or two complete cycles, the health warning clears and the reported capacity aligns to the actual 36.72Wh rating.
Laptop shuts down at 20–30% charge shown on the gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's discharge curve. The IC inherited voltage-to-percentage mapping from the old, degraded cell — so it miscalculates the remaining capacity and triggers shutdown before the cell is actually empty. It is not a defective battery. Run two or three full discharge-to-hibernate and full-recharge cycles without interruption. After calibration, the gauge will track accurately and the early shutdowns will stop — the cell sustains voltage above the 9.5V cutoff under combined CPU and display load.