About this replacement
HP Envy 13 Series — 14.8V Li-Polymer Replacement Battery (HSTNN-IB99)
This is a 14.8V, 2700mAh (39.96Wh) Li-Polymer battery for the HP Envy 13 ultrabook lineup. It fits the Envy 13, Envy 13-1000, Envy 13-1001TX, Envy 13-1002TX, and over 20 additional Envy 13 variants. OEM cross-references include HSTNN-IB99, HSTNN-XB99, BD04, and 538334-001.
- Envy 13 series compatibility: These models share a common 14.8V four-cell Li-Polymer architecture, the same physical connector pinout, and an identical BMS handshake protocol — which is why one cell services the entire Envy 13-1000 sub-series without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and controlled discharge on an Envy 13-1000 chassis. The BMS negotiated charge correctly, cell balancing stayed within spec, and no overcurrent trips occurred across the full discharge curve.
- First-install cycle on the Envy 13: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after swapping cells in these models.
BIOS reporting poor battery health immediately after fitting a new cell
HP's BIOS reads health data stored in the battery's EEPROM, not from live cell measurements. When a new cell is installed, the EEPROM profile doesn't match the host system's charge history, so the BIOS flags the battery as degraded or unknown before a single cycle runs. This is a data mismatch, not a faulty cell. Run one full discharge-to-hibernate then a full uninterrupted charge to 100% — the BIOS learn cycle rewrites its reference data and the health warning clears.
Envy 13 shuts down abruptly at 20–30% charge shown on screen
This happens when the cell can no longer hold voltage under combined CPU and display load — the voltage drops below the BMS cutoff threshold even though the fuel gauge still reads 20–30%. The fuel gauge IC calculates remaining charge from a model built on the old cell's behaviour, so its readout lags behind actual cell state. The fix is calibration: let the laptop discharge fully to automatic hibernate, then charge uninterrupted to 100% twice. After two calibration cycles the fuel gauge IC recalibrates against the new cell and shutdown below 30% stops.