About this replacement
HP Spectre X360 15 Series — 11.55V Li-Polymer Replacement Battery (KB06XL)
This is an 11.55V, 6750mAh (77.96Wh) lithium-polymer replacement battery for the HP Spectre X360 15 convertible laptop. It fits the 15-BL001NV, 15-BL081NG, 15-BL102NO, 15-DF0002NA, and over 100 additional Spectre X360 15 variants. OEM cross-references include KB06XL, HSTNN-DB7R, HSTNN-DB8I, and TPN-Q179.
- Spectre X360 15 platform fit: These models share the same 11.55V three-cell Li-Polymer architecture, identical BMS handshake protocol, and the same slim 5.50mm cell stack — which is why one part number spans the full BL and DF sub-series without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Spectre X360 15 platform. The BMS negotiated correctly with the EC, charge current stepped down as expected at the top-of-charge threshold, and no false protection trips occurred under sustained CPU and display load.
- First-cycle calibration on the Spectre X360 15: After installing, run one full discharge until the laptop hibernates on its own, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears in HP Support Assistant after every cell swap.
BIOS reporting poor battery health immediately after replacement
The HP EC reads cycle count, charge history, and rated capacity from the battery's EEPROM. When a new cell arrives, that EEPROM data does not match what the BIOS logged for the old cell, so Windows and HP Support Assistant flag health as "poor" or show 0% rated capacity. This is a data mismatch — not a fault with the new cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to rewrite its stored baseline against the new cell's actual readings. After one to two learn cycles, the health status corrects itself.
Spectre X360 15 shutting down at 20–30% charge shown
This happens when a degraded or uncalibrated cell cannot sustain voltage under the combined load of the processor boost state and the 4K OLED display at full brightness. The voltage drops below the EC's cutoff threshold before the fuel gauge reaches 0%, so the system cuts out with charge still displayed. On a new cell, this usually means the fuel gauge IC has not yet calibrated against the new chemistry. Run two full discharge-to-hibernate cycles, charging fully between each. If the shutdown persists below 15% after calibration, check that the EC firmware is current — HP SoftPaq SP84994 or later addresses voltage-floor thresholds on the X360 15 platform.