About this replacement
Lenovo Legion 7 16ACHg6 / Legion 5 Pro — 15.36V Li-Polymer Replacement Battery (L20C4PC1)
This is a 15.36V, 5100mAh (78.34Wh) Li-Polymer battery that replaces the original L20C4PC1 cell in the Lenovo Legion 7 16ACHg6 and Legion 5 Pro series gaming laptops. It fits the 82N6005WMB and related models across the Legion 7 and Legion 5 Pro lines. Voltage, connector pinout, and BMS communication protocol match the OEM spec.
- Legion 7 and Legion 5 Pro platform fit: Both the Legion 7 16ACHg6 and Legion 5 Pro 82JD series share the same 15.36V four-cell Li-Polymer architecture and use the same BMS handshake protocol. That common voltage rail and connector spec is why one part number covers both product lines without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on Legion hardware. The BMS completed CCCV charge without fault flags, and the fuel gauge IC accepted the new cell data after the BIOS battery learn cycle cleared.
- Post-install calibration on Legion BIOS: After fitting this battery, run one full discharge until the laptop hibernates on low-battery 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 — it is a firmware learning step, not a fault with the cell.
BIOS reporting battery health as poor immediately after replacement
The Legion BIOS reads health data from the battery's EEPROM, which stores charge cycle counts and rated Wh from the previous cell. When a new cell is installed, the EEPROM data does not match observed charge behaviour, so the BIOS flags the unit as degraded. This is not a defect in the replacement cell — it is a mismatch between stored historical data and a fresh chemistry baseline. Running the BIOS battery learn cycle (one full discharge to hibernate cutoff, then a full uninterrupted charge) resets that baseline. After one or two complete cycles, the health indicator should update to reflect the actual cell condition.
Laptop shuts down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The IC uses a stored discharge profile from the old cell to estimate remaining capacity, and that profile does not map accurately to the new chemistry until it has seen at least one full cycle. Under full CPU and display load, actual cell voltage drops faster than the gauge predicts, hitting the low-voltage cutoff before the displayed percentage reaches zero. Complete one full discharge-to-hibernate cycle, then charge to 100% without interruption — after that cycle the gauge IC recalibrates its endpoint and the shutdowns stop.