About this replacement
Fujitsu AH58/CM Series — 11.1V Li-ion Replacement Battery (FMVNBP190)
This is an 11.1V 4400mAh (48.84Wh) lithium-ion battery replacing OEM part FMVNBP190 and FMVNBP146. It fits the Fujitsu AH58/CM and a range of AH-series notebooks including the AH52/DA, AH77/D, and AH56/D. Slide it into the same bay, connect the same connector, and the notebook runs on battery again.
- AH-series platform fit: Fujitsu's AH-series notebooks across this generation share a common 11.1V three-cell Li-ion architecture, the same physical connector pinout, and a compatible BMS communication protocol — which is why a single part number covers more than twenty models in the range.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS handshake verification. The protection circuit responded correctly to over-charge and over-discharge thresholds, and the BIOS recognised the battery and reported state-of-charge without error codes during our test cycle.
- First-cycle calibration after install: After fitting, run the notebook on battery from 100% down to hibernate cutoff, then charge uninterrupted back to 100%. This gives the fuel gauge IC real data from the new cell and clears the inaccurate health warning the BIOS often displays after a cell swap.
BIOS reporting poor battery health immediately after replacement
Fujitsu's BIOS reads health data from the battery's EEPROM, which stores rated cycle count and capacity figures from the original cell. When a new cell arrives, those EEPROM values don't match what the BIOS last recorded, so it flags poor health or an unknown battery straight away. This is a firmware learning issue, not a fault with the new cell. Run one complete discharge-to-hibernate then a full uninterrupted charge to 100% — after one or two of these learn cycles the BIOS recalibrates and the warning clears.
Notebook shutting down abruptly at 20–30% charge shown
This happens when the cell voltage drops below the BMS cutoff threshold under full load — CPU boost, screen at max brightness, and active storage — even though the fuel gauge still reads 20–30%. The fuel gauge IC is reading open-circuit voltage, not the voltage under real load, so the displayed percentage is higher than the actual usable charge. The cell hits the 9V protection floor under load and the BMS trips the circuit before the OS can log a graceful shutdown. Let the battery calibrate through two full discharge-to-cutoff cycles; the fuel gauge IC will map the voltage curve of the new cell more accurately and the early shutdowns stop.