About this replacement
HP ProBook 640 G1 — 10.8V Li-ion Replacement Battery (CA06XL)
This is a 10.8V, 8400mAh (90.72Wh) Li-ion battery for the HP ProBook 640 G1, ProBook 640, ProBook 645, and ProBook 655. It replaces OEM part CA06XL and its associated cross-reference numbers. Install it when the original cell no longer holds a charge or the BIOS flags battery health as poor.
- ProBook 640/645/655 compatibility: These models share the same 10.8V battery rail, connector pinout, and SMBus BMS handshake protocol. One cell covers the full range without firmware conflicts.
- Bench tested on actual hardware: We ran this cell on a ProBook 640 G1 unit. The BMS initialised correctly, charge accepted across all three cells, and the fuel gauge IC began calibration without manual intervention.
- Post-install discharge cycle: After installing, run one full discharge down 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.
BIOS reporting battery health as poor after installing a new cell
The ProBook 640 G1 BIOS reads health data stored in the battery's EEPROM, not from live cell measurements. When a new cell is fitted, the EEPROM counters reset to zero and the BIOS interprets this as an unrecognised or degraded pack. This is not a fault with the replacement cell. Run the battery learn cycle — discharge fully to hibernate cutoff, then charge to 100% without interruption — and the BIOS health indicator will update correctly within one to two cycles.
Laptop shuts down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The reported percentage and the real cell voltage diverge, and the system cuts power before the gauge catches up. It is most likely to occur under full CPU and display load, where voltage sag is steepest. Complete two full discharge-to-hibernate and uninterrupted full-charge cycles, and the fuel gauge will track actual cell voltage accurately — confirmed at 10.8V nominal under load in our bench tests.