About this replacement
Fujitsu Lifebook BH531 / SH531 / LH531 — 11.1V Li-ion Replacement Battery (FMVNBP195)
This is an 11.1V 5000mAh (55.5Wh) lithium-ion replacement battery for the Fujitsu Lifebook BH531, SH531, and LH531 notebook computers. It matches the OEM specification for voltage, capacity, and connector, and slots directly into the battery bay on all three models. OEM part numbers covered include FMVNBP195, FPCBP274, S26391-F545-B100, S26391-F545-E100, and S26391-F545-L100.
- BH531 / SH531 / LH531 platform fit: All three Lifebook models share the same battery bay dimensions, 11.1V power rail, and connector pinout. The BMS handshake protocol is identical across the series, so one cell revision covers all three chassis without firmware conflicts.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a BH531 unit. The BMS accepted the new cell without error, charge termination triggered correctly at 12.6V, and the protection circuit cut off cleanly at the low-voltage threshold before any cell damage occurred.
- Post-swap BIOS calibration on the BH531 series: 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 Lifebook models.
BIOS reporting poor battery health immediately after fitting a new cell
The Lifebook BIOS reads health data from EEPROM registers that carry over from the old cell. A fresh cell has no accumulated cycle data, but the BIOS interprets the mismatch as degradation rather than a new battery. This is a firmware read issue, not a fault with the replacement cell. Running the battery learn cycle — one full discharge to hibernate cutoff followed by an uninterrupted charge to 100% — forces the BIOS to rewrite its reference values against the new cell chemistry and clear the false health flag.
Lifebook shutting down without warning at 20–30% charge shown
This happens when the cell voltage drops below what the system can sustain under combined CPU and display load, even though the fuel gauge still reads 20–30%. The fuel gauge IC on the BH531 series maps voltage to percentage using calibration data from the old cell, so the reading lags behind the actual voltage cliff. The laptop cuts power because the hardware voltage rail collapses, not because the OS triggers a shutdown. Run the full discharge-to-hibernate and recharge cycle to recalibrate the fuel gauge IC against the new cell's discharge curve, and the percentage readings will track accurately from that point.