CX03XL HP EliteBook X360 830 G7 Compatible Battery 11.55V

HP EliteBook X360 830 G7 / 855 G7 / 830 G8 — 11.55V Li-Polymer Replacement Battery (CX03XL)

This is an 11.55V, 4200mAh (48.51Wh) Li-Polymer replacement battery for the HP EliteBook X360 830 G7, EliteBook 855 G7, and EliteBook X360 830 G8. These are 2-in-1 convertible laptops that share a common battery platform across the G7 and G8 refresh. It replaces OEM part numbers CX03XL, CX03053XL, HSTNN-LB8R, L77624-421, and L78551-005.

• EliteBook X360 and 855 G7/G8 shared platform: HP used the same 3-cell CX03 battery configuration across the 830 G7, 855 G7, and 830 G8. All three run the same 11.55V rail, use the same physical connector, and communicate over the same SMBus BMS handshake — so one cell fits all three without firmware conflict.
• Bench tested on actual hardware: We ran this cell on an EliteBook X360 830 G7 unit. The BMS negotiated correctly on first insertion, charge current ramped normally to CC phase, and the BIOS recognised the battery without any unrecognised-device flag.
• First-cycle calibration on EliteBook platforms: After fitting, run the laptop on battery until it hibernates from low charge, then charge uninterrupted to 100% without waking the system mid-cycle. This resets the BIOS battery learn cycle and clears the inaccurate health warning that shows up after every cell swap on EliteBook firmware.

BIOS reporting battery health as poor immediately after fitting a new CX03XL

The EliteBook BIOS reads health data from the battery's EEPROM, which stores charge-cycle counts and wear metrics from the old cell. When a new cell is installed, the EEPROM data is reset, but the BIOS still compares it against the previous charge history it cached. This mismatch triggers a false "battery health poor" or "consider replacing battery" warning. Running one complete discharge-to-hibernate cycle followed by a full uninterrupted charge clears the cached data and lets the BIOS re-establish its baseline. After two to three full cycles, the health indicator should display correctly.

Laptop shutting down at 20–30% shown on the fuel gauge after battery replacement

This happens because the fuel gauge IC — the chip that estimates remaining capacity — is still calibrated to the old cell's discharge curve. The new cell holds voltage well until it hits a steeper voltage cliff at low state-of-charge, and the gauge hasn't learned where that cliff is yet. Under combined CPU and display load, the voltage drops faster than the uncalibrated gauge expects, triggering a hard shutdown before the displayed percentage reaches zero. Run two to three full discharge-to-hibernate cycles, charging back to 100% each time, and the gauge will map the new cell's curve. After calibration, shutdown should not occur above 5% remaining.