About this replacement
Lenovo ThinkPad X1 Carbon 3460-22U Series — 14.8V Li-Polymer Replacement Battery (45N1070)
This is a 14.8V, 3100mAh (45.88Wh) Li-Polymer replacement battery for the Lenovo ThinkPad X1 Carbon. It fits the 3460-22U, 3460-23U, 3460-25U, 3444-53U, and related variants. It replaces OEM part numbers 45N1070 and 45N1071.
- X1 Carbon 3460 and 3444 series fit: These models share the same 14.8V battery rail, physical footprint, and connector pinout. The BMS handshake protocol is consistent across the listed variants, so one cell works across the full range without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the X1 Carbon platform. The BMS communicated correctly with the host, charge termination triggered at the expected voltage ceiling, and no protection-circuit trips occurred under sustained CPU and display load.
- Post-install calibration on the X1 Carbon: After fitting the new cell, 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 on this platform.
BIOS reporting poor battery health immediately after replacement
The X1 Carbon reads battery health data from EEPROM stored on the old cell. When a new cell installs, the BIOS compares live readings against stale EEPROM values and flags a mismatch as poor health. This is not a fault with the replacement cell. Running the Lenovo battery learn cycle — one full discharge to hibernate cutoff followed by a full uninterrupted charge — writes fresh calibration data and resolves the warning. After one complete cycle, the health status should return to normal in both the BIOS and Lenovo Vantage.
Laptop shutting down with 20–30% charge still shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The displayed percentage is based on old reference data, so the system hits a real voltage floor while the gauge still reads high. Under full CPU and display load, the cell voltage drops faster than the IC predicts, triggering an emergency shutdown. Run two full discharge-to-hibernate and full-charge cycles — after that, the fuel gauge IC builds an accurate model of the new cell and the shutdowns stop. Confirm calibration is complete when the battery reaches 0% at hibernate without an abrupt cutoff above 15%.