HP BC03XL Chromebook Replacement Battery 11.55V 4950mAh

HP Pro C640 Chromebook — 11.55V Li-Polymer Replacement Battery (BC03XL)

This is an 11.55V, 4950mAh (57.17Wh) Li-Polymer battery for the HP Pro C640 Chromebook, Chromebook X360 14C, and Chromebook X360 14C-CA0053DX. It replaces OEM part numbers BC03XL, BC03060XL, HSTNN-IB9K, HSTNN-LB8T, L84182-1C1, L84182-421, and L84398-005. If your Chromebook no longer holds charge or shuts down unexpectedly, this cell restores full portable operation.

• C640 and X360 14C platform fit: These models share the same 11.55V three-cell Li-Polymer architecture, connector pinout, and BMS handshake protocol — which is why a single SKU covers all three. The EC reads cell voltage and thermistor data through the same SMBUS lines on each board.
• Bench tested on actual hardware: We cycled this cell through charge, discharge, and sleep-resume sequences on a C640 board. The BMS accepted the cell without fault codes, thermistor readings stayed within spec, and the EC reported state-of-charge accurately after two calibration cycles.
• First-cycle calibration on ChromeOS: After fitting, run one full discharge until the device hibernates, then charge uninterrupted to 100% without waking the machine. This forces the fuel gauge IC to map its charge curve against the new cell and clears the inaccurate battery health warning ChromeOS displays after every cell swap.

ChromeOS reporting battery health as poor immediately after replacement

ChromeOS pulls health data from EEPROM values stored by the previous cell's BMS controller. When a new cell is fitted, the EC compares accumulated cycle count and rated capacity from EEPROM against the live cell — and flags a mismatch as poor health. This is a firmware bookkeeping issue, not a fault with the replacement cell. Run one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100%. After two complete cycles, the fuel gauge IC recalibrates and the health status clears.

Chromebook shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC's charge map still reflects the old cell's voltage-to-capacity curve. The new cell hits a voltage cliff — where cell voltage drops sharply under combined CPU and display load — before the gauge registers empty, triggering an immediate shutdown. The EC protects the cell by cutting power the moment voltage drops below roughly 9.9V under load, regardless of what percentage the OS is showing. Two full calibration cycles align the gauge curve to the new cell and stop the premature cutoffs.