About this replacement
Fujitsu FMV-LifeBook B8220 — 7.2V Li-ion Replacement Battery (FMVNBP149)
This 7.2V, 7800mAh (56.16Wh) Li-ion battery replaces the original cell in the Fujitsu FMV-LifeBook B8220 and related LifeBook B-series and TC-series notebooks. It also fits the FMV-LIFEBOOK TC8230, LifeBook B6210, and LifeBook B6220. OEM part numbers covered: FMVNBP149, FMVNBP150, FPCBP152, and FPCBP152AP.
- B-series and TC8230 shared platform: These models run the same 7.2V battery rail with an identical 6-cell connector and BMS handshake protocol. One cell covers the full compatibility group — the BMS on each model reads the same EEPROM registers and accepts the same charge profile.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a B8220 unit. The BMS accepted the cell without error flags, balanced across all six cells within two cycles, and held the full 7.2V rail under sustained CPU and display load.
- First-cycle recalibration on LifeBook B-series: After fitting this cell, 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 appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting a new cell
The LifeBook BIOS stores cycle count and health data in the old cell's EEPROM. When a new cell goes in, the BIOS compares its learned values against a blank or mismatched EEPROM record and flags poor health. This is a firmware-side artefact, not a fault with the replacement cell. Running the full discharge-to-hibernate then uninterrupted charge sequence forces the BIOS to rewrite its battery learn table against the new cell's actual capacity data. After one complete calibration cycle the health indicator should return to normal.
Laptop shuts down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC's stored discharge curve no longer matches the new cell's actual voltage-versus-capacity profile. Under combined CPU and display load, the cell voltage drops faster than the fuel gauge predicts, hitting the BMS low-voltage cutoff while the OS still shows charge remaining. The fix is calibration: discharge fully to automatic hibernate, do not interrupt, then charge to 100% in one session. After two to three full cycles the fuel gauge IC recalculates the curve and the shutdown point realigns to the true remaining capacity — typically below 5% shown.