About this replacement
Lenovo IdeaPad U430 Series — 7.4V Li-Polymer Replacement Battery (L12L4P62)
This is a 7.4V, 7100mAh (52.54Wh) Li-Polymer replacement battery for the Lenovo IdeaPad U430 series 14-inch ultrabook. It fits the IdeaPad U430, U430 Touch, U430P, and U430T. It replaces OEM part numbers L12L4P62 and L12M4P62.
- U430 series fit: The U430, U430 Touch, U430P, and U430T all run the same 7.4V two-cell Li-Polymer pack with an identical connector and BMS handshake. Lenovo used the same charge controller across this ultrabook line, so one cell works across all variants without adapter or modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the U430 platform. The BMS communicated correctly with the EC controller, charge current stepped down at 4.2V per cell as expected, and the pack reported accurate state-of-charge data to the OS throughout.
- Post-install calibration on the U430: After fitting this 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 in Lenovo Vantage after every cell swap.
BIOS reporting poor battery health immediately after replacement
The U430 EC stores charge history and cycle count in EEPROM on the old cell. When a new cell goes in, the BIOS reads no learned data and flags the battery as degraded or unknown. This is not a fault with the new cell — it is a mismatch between the EEPROM log and a fresh chemistry. Run one complete discharge-to-hibernate cycle followed by a full uninterrupted charge. After two to three cycles the BIOS recalibrates and the health warning clears.
Laptop shuts down hard at 20–30% charge shown on screen
This happens when the fuel gauge IC is still calibrated against the old, degraded cell. A new cell with higher actual capacity hits a voltage cliff the old fuel map does not expect, so the gauge reads 25% while the cell is already below the BMS cutoff threshold under CPU and display load. The fix is a full discharge-to-hibernate calibration cycle — do not interrupt charging during the recovery charge. After the cycle completes, the fuel gauge IC maps its discharge curve against the new cell and the early shutdowns stop. Confirm the fix by watching the voltage hold above 7.0V at 15% reported charge.