About this replacement
HP Envy 15-AS005NG — 11.55V Li-Polymer Replacement Battery (849047-541)
This is an 11.55V, 4250mAh (49.09Wh) lithium-polymer replacement battery for the HP Envy 15-AS005NG series, including the W8Y52EA, W8Y50EA, and W9T89EA variants. It fits the three-cell VS03XL form factor and connects via the original chassis connector without modification. Part numbers 849313-850, HSTNN-UB6Y, TPN-I125, and VS03XL all cross-reference to this cell.
- Envy 15-AS series platform fit: These variants share the same three-cell LiPo tray, voltage rail, and BMS handshake protocol. The 11.55V nominal output matches the charging circuit on the AS-series motherboard, so the charge controller accepts the cell without firmware conflict.
- Bench tested on actual hardware: We ran this cell on an Envy 15-AS chassis and monitored BMS communication through full charge cycles. The protection circuit engaged correctly at both the low-voltage cutoff and the thermal threshold — no false trips under sustained CPU and display load.
- Post-install calibration on the AS series: After fitting, drain the battery to hibernate-cutoff under normal workload, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell's actual capacity curve and clears the inaccurate health warning that appears on every cell swap in this platform.
BIOS reporting poor battery health immediately after replacement
The HP Envy 15-AS series stores battery health data in EEPROM on the old cell. When a new cell is fitted, the BIOS compares its learned cycle data against the new cell's EEPROM signature and flags a mismatch as degraded health. This is not a fault with the replacement cell — it is a firmware state issue. Running one complete discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the learn cycle and overwrites the stale EEPROM-referenced health status. After two to three full cycles, the reported health figure stabilises at the new cell's actual capacity.
Laptop shuts down at 20–30% charge shown on the Envy 15-AS
This happens when the fuel gauge IC has not yet calibrated against the new cell's discharge curve. The IC still uses the old cell's voltage-to-capacity map, so it misreads the voltage cliff — the point where cell voltage drops sharply under CPU plus display load — as a valid 20–30% reading. The system hits the low-voltage hardware cutoff before the gauge reaches 0%. Perform a full discharge to hibernate-cutoff, then charge to 100% without interruption; repeat this twice and the fuel gauge IC recalculates the correct curve down to 11.1V cutoff.