About this replacement
HP UG04XL — 15.4V Li-Polymer Replacement Battery (996QA166H / HSTNN-IB9B)
This is a 15.4V, 2950mAh (45.43Wh) lithium-polymer replacement battery for HP notebooks and laptops using OEM part numbers 996QA166H, HSTNN-IB9B, L71493-1C1, L71607-005, UG04XL, or UG04046XL. It replaces a degraded original cell that no longer sustains charge under normal laptop load. Confirm your part number on the underside of the original battery before ordering.
- OEM part number cross-reference: These part numbers — 996QA166H, HSTNN-IB9B, L71493-1C1, L71607-005, UG04XL, UG04046XL — all reference the same 15.4V four-cell LiPo pack. HP uses multiple internal codes for the same battery across procurement runs; the connector pinout, BMS handshake protocol, and voltage rail are identical across all variants.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on compatible HP hardware. The BMS communicated correctly with the system board, charge acceptance was normal from 0% to 100%, and no fault codes were triggered during the test sequence.
- Post-install calibration: After fitting this cell, 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 every cell swap — skipping this step leaves the fuel gauge reading stale data from the old cell.
BIOS reporting battery health as poor immediately after replacement
HP's BIOS stores battery health data in the EEPROM of the original cell. When a new cell is installed, the BIOS compares its learned data against the new EEPROM and flags a mismatch as poor health. This is not a fault with the replacement battery — it is a calibration state. Run one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100%, and the BIOS will re-learn the new cell's capacity curve and clear the warning.
Laptop shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The displayed percentage does not match the cell's actual state of charge, so the system hits the low-voltage cutoff before the gauge reaches 0%. The fix is two to three full discharge-to-hibernate and full-recharge cycles — each pass gives the fuel gauge IC fresh data to recalculate the curve. After calibration, shutdown should not occur above 5% displayed charge.