About this replacement
Lenovo IdeaPad Y450 Series — 11.1V Li-ion Replacement Battery (55Y2054)
This 11.1V, 4400mAh Li-ion battery replaces the original cell in the Lenovo IdeaPad Y450 laptop line. It fits the IdeaPad Y450, Y450 20020, Y450 4189, and Y450A, among other variants in the Y450 family. OEM part numbers covered include 55Y2054, L08L6D13, L08O6D13, and L08S6D13.
- Y450 series fit: All Y450 variants listed share the same 11.1V voltage rail, connector pinout, and BMS handshake protocol. One cell covers the full range without adapter or modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Y450 unit. The BMS negotiated correctly, charge termination triggered at 100%, and no fault codes were logged during the test sequence.
- Post-install discharge cycle: After fitting this battery, run one full discharge 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 poor battery health after replacement on the Y450
The Y450 BIOS reads health data from EEPROM registers that were written by the original cell. A new cell arrives with different EEPROM values, so the BIOS flags it as degraded even when the cell is brand new. This is not a fault with the replacement battery. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% prompts the BIOS to rewrite the learn cycle and clears the warning on the next boot.
Laptop shuts down at 20–30% shown on the fuel gauge after swap
This happens because the fuel gauge IC is still calibrated against the old cell's discharge curve. The new cell hits a voltage cliff under combined CPU and display load before the OS gauge reaches zero, triggering a hard shutdown. The gauge and the actual cell capacity are out of sync. Complete two to three full discharge-to-hibernate and full charge cycles — the fuel gauge IC recalibrates against the new cell and the shutdowns stop once the readings align.