About this replacement
HP Spectre XT TouchSmart 15-4000eg — 14.8V Li-Polymer Replacement Battery (PW04XL)
This is a 14.8V, 3200mAh (47.36Wh) lithium-polymer battery replacing part number PW04XL in the HP Spectre XT TouchSmart 15 series. It fits the 15-4000eg, 15-4100, 15-4095ca, and TPN-C105 among other Spectre XT TouchSmart Ultrabook variants. The flat 4.70mm profile matches the original cell envelope for correct seating inside the chassis.
- Spectre XT TouchSmart 15 series compatibility: These models share the same 14.8V four-cell configuration, PW04XL connector pinout, and BMS handshake protocol — the same replacement cell works across the full 15-4000 and 15-4100 platform without modification.
- Bench tested on actual hardware: We ran this cell through charge-discharge cycles on the TPN-C105 platform, confirmed the BMS accepted the cell without fault codes, and verified charge termination occurred correctly at full capacity.
- BIOS learn cycle after installation: 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 the Spectre XT platform.
BIOS reporting battery health as poor immediately after replacement
The HP Spectre XT BIOS reads health status from EEPROM data embedded in the battery controller — not from live cell voltage. When a new cell is fitted, the EEPROM starts at a neutral or mismatched state, and the BIOS interprets this as degraded health. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by a complete uninterrupted charge gives the fuel gauge IC enough data to write accurate values back to the EEPROM and clear 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 voltage curve. The displayed percentage still reflects the old cell's characteristics, so the laptop cuts power when the new cell hits its minimum safe voltage — typically around 11.0V under full CPU and display load — while the OS still shows 20–30% remaining. It is not a defective cell. Complete two to three full discharge-and-charge cycles and the gauge IC recalibrates; after that, shutdown will align with the percentage shown on screen.