About this replacement
Lenovo Pavilion x360 13-u018TU — 7.72V Li-Polymer Replacement Battery (L21C2PJ0)
This 7.72V, 2700mAh (20.84Wh) Li-Polymer cell is a direct replacement for the Lenovo Pavilion x360 13-u018TU convertible laptop. It matches the original voltage rail and connector pinout used across the x360 13-u018TU platform. OEM part numbers covered include L21C2PJ0, L21D2PJ0, L21L2PJ0, L21M2PJ0, and SB11B48820.
- x360 13-u018TU platform fit: These OEM part numbers share a common 7.72V two-cell Li-Polymer architecture, identical BMS connector layout, and the same EEPROM handshake protocol. Any of the five listed part numbers will seat and communicate correctly in this chassis without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the x360 platform. The BMS handshake completed on first connection, charge acceptance started immediately at standard 5V input, and the protection circuit responded correctly to cutoff at both ends of the voltage range.
- BIOS learn cycle after install: After fitting this cell, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100% without unplugging. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on Lenovo x360 units.
Laptop shutting down at 20–30% shown on the x360 13-u018TU
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. Under combined CPU and display load, the cell voltage drops faster than the uncalibrated gauge expects, triggering a premature shutdown. It is not a fault with the cell itself. Run two to three full discharge-to-hibernate cycles followed by uninterrupted charges to 100% — shutdowns at false percentages stop once the gauge IC maps the real voltage floor, typically around 6.0V under load.
BIOS reporting wrong Wh rating after installing replacement cell
The Wh figure shown in BIOS or device manager is read from EEPROM data stored in the battery's controller chip, not calculated live from the cell. When a replacement cell's EEPROM is programmed to a slightly different rated value than the original, the system displays a mismatch. This does not affect charge acceptance, discharge behaviour, or cycle count tracking. Check the actual watt-hour value against the cell label — 20.84Wh — and confirm the discrepancy is only in the reported figure before assuming a fault.