About this replacement
HP Pavilion X360 11-U000 Series — 11.55V Li-ion Replacement Battery (NU03XL)
This is an 11.55V, 3600mAh (41.58Wh) Li-ion battery for the HP Pavilion X360 11-U000 series convertible laptop. It replaces OEM part numbers NU03XL, HSTNN-UB6V, and TPN-W117, among others. It fits the 11-U000, 11-U000ng, 11-U001ng, 11-U002ng, and over 200 additional X360 11-U variants.
- X360 11-U series compatibility: All 11-U models share the same 11.55V three-cell architecture, connector pinout, and BMS handshake protocol. The TPN-C128 and TPN-W117 designations both map to the same internal cell configuration, so one battery covers the full lineup.
- Bench tested on actual hardware: We ran this cell on an 11-U unit and confirmed the BMS negotiated correctly with the EC controller. The charge circuit accepted the full 3600mAh draw without triggering a fault code, and the fuel gauge IC responded to the new cell data as expected.
- Post-install discharge cycle on the X360: After fitting this battery, run the laptop on battery power until it hibernates at low charge, then charge uninterrupted to 100% without interruption. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting a new cell
The HP BIOS reads health data stored in the battery's EEPROM, not from live cell measurements alone. When you swap cells, the EEPROM values from the old pack can persist in the system's embedded controller memory, causing the BIOS to flag the new battery as degraded. This is not a fault with the replacement cell. Running one complete discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the learn cycle and rewrites the EC's stored capacity baseline. After that cycle, the BIOS health indicator should return to normal.
Pavilion X360 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC's stored discharge curve no longer matches the actual cell. Under full load — CPU boost plus touchscreen display — voltage drops faster than the gauge predicts, and the system hits the hardware cutoff threshold before the percentage reaches zero. The gauge was calibrated to the old cell's curve and hasn't updated yet. Run two or three full discharge-to-hibernate and full-charge cycles to give the fuel gauge IC enough data to recalibrate against the new cell. After calibration, the shutdown percentage should track accurately down to the configured low-battery cutoff, typically around 5%.