Fujitsu LifeBook LH520 Compatible Battery 11.1V 4400mAh

Fujitsu LifeBook LH520 / A530 Series — 11.1V Li-ion Replacement Battery (CP477891-01)

This 11.1V 4400mAh Li-ion battery pack replaces the original CP477891-01 / FPCBP250 / FPCBP274 cells used in the Fujitsu LifeBook LH520, LH530, A530, and A531. It uses the same connector pinout and BMS communication protocol as the factory pack. Capacity is 4400mAh (48.84Wh) — matched to the OEM specification.

• LifeBook LH and A series compatibility: The LH520, LH530, A530, and A531 share the same 11.1V three-cell battery bay, connector, and BMS handshake protocol — that is why one pack covers all four models. The fuel gauge IC on each motherboard reads the same EEPROM data structure regardless of which model it is installed in.
• Bench tested on actual hardware: We ran this pack on a LifeBook LH520 motherboard. The BMS connected cleanly, charge current ramp-up behaved normally from 0% to 100%, and no over-temperature or cell-fault flags triggered during the full charge cycle.
• Post-install calibration on LifeBook systems: After fitting this pack, run the laptop on battery until it hibernates from low charge — do not interrupt. Then charge it to 100% uninterrupted. This forces the LifeBook's fuel gauge IC to build a new capacity baseline against the fresh cells and clears the inaccurate health warning the BIOS typically displays after any cell swap.

BIOS reporting battery health as poor immediately after replacement

The LifeBook BIOS reads health status from EEPROM data written by the original battery pack. When a new pack is installed, that EEPROM baseline does not yet match the fresh cell chemistry, so the BIOS flags the battery as degraded even though the cells are new. This is a calibration state, not a fault. Run one full discharge-to-hibernate cycle followed by an uninterrupted full charge. After one to two cycles the BIOS learn routine rewrites its baseline and the health warning clears.

LifeBook shutting down abruptly at 20–30% charge shown

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The IC predicts 20–30% remaining based on the old cell's curve, but the new cells hit their low-voltage cutoff at a different point — the system shuts down before the gauge catches up. It is not a defective pack. Complete two full discharge-to-hibernate-then-100%-charge cycles. After that the gauge IC maps the correct voltage cliff for these cells and the shutdown behaviour stops. If it persists past three cycles, check that the BIOS charge-limit setting is not capped below 100%.