About this replacement
Lenovo ThinkBook 13x ITG — 15.48V Li-Polymer Replacement Battery (L20C4PD1)
This is a 15.48V, 3400mAh (52.63Wh) Li-Polymer battery for the Lenovo ThinkBook 13x ITG and ThinkBook Plus G2 ITG series ultrabooks. It replaces OEM part numbers L20C4PD1, L20D4PD1, L20M4PD1, SB11B65324, and SB11B65326. The battery slots into the same connector and BMS handshake point as the factory cell.
- ThinkBook 13x ITG and Plus G2 ITG compatibility: These models share a 15.48V four-cell Li-Polymer architecture with a unified connector and BMS communication protocol. The EEPROM on each cell carries chemistry and rated Wh data that the Lenovo firmware reads directly at boot — swapping like-for-like keeps that handshake intact.
- Bench tested on actual hardware: We ran this cell on a ThinkBook 13x ITG under a sustained CPU and display load cycle. The BMS held charge termination correctly at 15.48V and the fuel gauge IC tracked cell voltage within normal drift across three full cycles.
- First cycle reset after install: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This walks the BIOS through its battery learn cycle against the new cell and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor immediately after replacement
The ThinkBook firmware reads cycle count and health data stored in the outgoing cell's EEPROM. When a new cell arrives with a blank or factory-default EEPROM, the BIOS flags it as unknown or degraded — not because anything is wrong, but because it has no historical data to compare. This is not a fault with the replacement cell. Running the full discharge-to-hibernate then uninterrupted charge-to-100% sequence lets the BIOS write a new baseline. After two to three cycles, the health readout in Lenovo Vantage or the Windows battery report normalises.
Laptop shutting down at 20–30% battery shown on screen
This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The percentage shown is based on a voltage-to-capacity map built from the previous cell — the new cell hits a steeper voltage cliff at a different point, and the system interprets that as a hard shutdown threshold. It is not a defective battery. The fix is the same calibration cycle: discharge fully to hibernate, recharge to 100% uninterrupted, and repeat once more. After two cycles, the fuel gauge re-maps the curve and shutdowns at low percentages stop. If the issue persists after three cycles, check that Lenovo Vantage is not enforcing a custom discharge floor below 20%.