About this replacement
HP ZBook Firefly 15 G8 / EliteBook 850 G7-G8 — 11.55V Li-Polymer Replacement Battery (CC03053XL)
This is an 11.55V, 4600mAh (53.13Wh) Li-Polymer replacement battery for the HP ZBook Firefly 15 G8 381M8Pa, ZBook Firefly 15 G7, EliteBook 850 G7, and EliteBook 850 G8 mobile workstations. It matches OEM part numbers CC03053XL, CC03XL, HSTNN-DB9Q, HSTNN-IB9F, and L77608 series references. Voltage, connector, and BMS handshake match what HP's EC firmware expects from this cell generation.
- ZBook Firefly 15 G7/G8 and EliteBook 850 G7/G8 compatibility: These platforms share the same 11.55V three-cell Li-Polymer architecture, the CC03 connector pinout, and the same EC firmware battery-authentication sequence — which is why one cell SKU covers the entire lineup.
- Bench tested on actual hardware: We ran this cell on a ZBook Firefly 15 G8 chassis. The EC recognised the pack without error codes, the BMS completed charge handshake normally, and the fuel gauge IC began tracking state-of-charge across the first two cycles.
- First-cycle calibration after install: After fitting, run the laptop on battery until it hibernates at low-charge cutoff, then charge uninterrupted to 100% without using the machine. This gives the fuel gauge IC a full reference window against the new cell and clears the inaccurate health warning HP BIOS posts after every cell swap.
Why HP BIOS flags this replacement as "poor health" immediately after install
HP's EC reads EEPROM data written to the original cell over its service life — cycle count, wear state, and calibrated capacity. A new cell ships with blank or factory-default EEPROM values, so the BIOS compares those defaults against the old cell's last-written state and raises a health warning. This is not a fault with the new battery. One complete discharge-to-hibernate followed by a full uninterrupted charge resets the learn cycle and writes current EEPROM data from the new cell, which clears the warning on the next boot.
ZBook Firefly 15 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 actual voltage curve. The gauge reports 25% remaining while the cell voltage has already dropped below the EC's shutdown threshold under full CPU-plus-display load — so the system cuts power without warning. The fix is completing two to three full discharge-recharge cycles so the IC maps the new cell's voltage-to-capacity relationship accurately. After calibration, the shutdown threshold aligns correctly with what the gauge displays, and the cutoff moves to the expected range near 5%.