About this replacement
Asus N45 Series — 11.1V Li-ion Replacement Battery (A32-N55)
This is a 11.1V, 4400mAh (48.84Wh) Li-ion replacement battery for the Asus N45 notebook line. It fits the N45, N45E, N45S, N45SF, and more than twenty additional N45-series variants. The OEM part numbers are A32-N55 and 07G016HY1875.
- N45-series compatibility: All covered models share the same 11.1V three-cell rail, identical connector pinout, and the same BMS handshake protocol — so one cell works across the full N45 lineup without firmware differences or adapter modifications.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an N45SF. The BMS negotiated correctly with the system board on first connection, and charge termination triggered cleanly at full capacity with no overcharge event detected.
- Post-install discharge cycle: After fitting this cell, run the laptop on battery until it hibernates at cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor immediately after fitting a new cell
The N45 BIOS reads health data from EEPROM embedded in the battery pack, not from live cell voltage. When a new cell arrives, the EEPROM contains factory default values that don't match the BIOS's stored baseline for the old pack. The system flags this mismatch as poor health even though the cell is at full capacity. Run one complete discharge-to-hibernate cycle followed by a full uninterrupted charge — the BIOS resets its learn cycle and the health warning clears.
Laptop shuts down abruptly while the OS still shows 20–25% remaining
This is a voltage cliff failure, not a faulty gauge. Under combined CPU and display load, cell voltage drops faster than the fuel gauge IC can recalculate. The protection circuit cuts power at its minimum voltage threshold — typically around 9.0V for an 11.1V pack — before the displayed percentage reaches zero. The fuel gauge IC needs two to three full calibration cycles against the new cell to map the actual discharge curve. Charge to 100%, run to hibernate cutoff twice, and the shutdowns at false-percentage readings will stop.