HP Pavilion x2 Replacement Battery NB02XL 7.4V 3750mAh

HP Pavilion x2 — 7.4V Li-Polymer Replacement Battery (NB02XL)

This is a 7.4V, 3750mAh Li-Polymer replacement battery for the HP Pavilion x2 detachable hybrid tablet-laptop. It fits the Pavilion x2 11.6" series, including models 11-H010NR and 11-H015TU, and uses OEM part numbers NB02XL, HSTNN-DB5K, and 726596-001 among others. The battery sits in the tablet portion of the unit, not the keyboard dock.

• Pavilion x2 tablet unit compatibility: The Pavilion x2 series routes power through the tablet section only — the keyboard dock carries no cell. All listed models share the same 7.4V voltage rail, flat Li-Polymer form factor at 134.08 x 132.10 x 4.50 mm, and the same BMS handshake protocol, which is why one cell covers the full variant range.
• Bench tested on actual hardware: We ran this cell through full charge and load cycles on the Pavilion x2 platform. The BMS communicated correctly with the HP charge controller, accepted a full charge without tripping the protection circuit, and reported cell status back to the OS without error flags.
• First-cycle calibration on the Pavilion x2: After fitting this cell, 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 on this platform.

BIOS reporting poor battery health immediately after fitting the NB02XL

HP's battery health check in BIOS reads EEPROM data that the old cell wrote during its service life. When a new cell goes in, the BIOS still holds those degraded charge-cycle counts and flags the battery as worn before it has run a single cycle. This is not a fault with the replacement cell. Run the HP Battery Check utility — if it clears after one full charge-discharge cycle, the EEPROM data has been overwritten correctly. If it persists past three cycles, check that the BIOS firmware is current, as older versions on the x2 had a known misread on Li-Polymer cells.

Pavilion x2 shutting down abruptly while the OS still shows 20–25% remaining

This happens when the fuel gauge IC on the tablet board has not yet calibrated against the new cell's actual discharge curve. The IC uses a stored model from the old cell, which causes it to misread remaining capacity — the cell voltage drops below the cutoff threshold before the gauge reaches zero. Complete two full discharge-to-hibernate and uninterrupted charge-to-100% cycles to force the IC to relearn the curve. After calibration, the cutoff should align with the OS percentage display at or below 5%. If the shutdown point does not shift after three cycles, check that the tablet's charge port is delivering a clean 5V input during charging.