About this replacement
Asus Pro P3540FA / P3540FB Series — 15.4V Li-Polymer Replacement Battery (C41N1832)
This is a 15.4V, 4500mAh (69.3Wh) lithium-polymer replacement battery for the Asus Pro P3540FA and P3540FB series business notebooks. It fits the EJ0056R, EJ0811R, BQ0253T, and P574FB variants, along with 79 additional confirmed models. OEM part numbers include C41N1832, 0B200-03330, and 0B200-03630000.
- P3540FA and P3540FB platform fit: These models share the same 15.4V four-cell Li-Polymer architecture, connector pinout, and BMS handshake protocol — one cell covers the full range without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a P3540FA unit. The BMS negotiated correctly with the EC, charge termination triggered at rated voltage, and no over-temperature flags appeared during a full load cycle.
- Post-install battery learn cycle: After fitting this cell, run the laptop 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.
Why the P3540FA BIOS reports poor battery health immediately after a cell swap
The P3540FA stores battery health data in EEPROM on the old cell. When a new cell is installed, the EC reads stale cycle-count and capacity data that does not match the replacement. The BIOS then flags the battery as degraded — not because the new cell is faulty, but because the health register has not been recalibrated. Running one complete discharge-to-hibernate and full recharge cycle rewrites the learn data and resolves the warning.
Laptop shuts down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The gauge loses accuracy at the low end and the laptop cuts power before the displayed percentage reaches zero. It is not a cell defect — the IC needs two or three full charge and discharge cycles to map the new cell correctly. After calibration, the shutdown threshold will track accurately down to the correct cutoff voltage near 12.0V under load.