Lenovo Y9000K Compatible Battery 15.36V 5250mAh L19M4PC2

Lenovo Legion Y9000K 2020 — 15.36V Li-Polymer Replacement Battery (L19M4PC2)

This 15.36V, 5250mAh (80.64Wh) lithium-polymer cell replaces the factory battery in the Lenovo Legion Y9000K 2020 and related Legion 7 / Legion 7i 15-inch platforms. It also fits the Y7000 2020 and other models sharing the L19M4PC2 / L19C4PC2 OEM part numbers. Voltage, connector pinout, and BMS communication protocol match the original spec.

• Legion 7 / Y9000K platform fitment: These models share a common 15.36V four-cell architecture, the same physical connector, and an identical BMS handshake sequence. That is why a single cell covers the Y9000K 2020, Legion 7 15IMH, Legion 7i 15IMH, and Y7000 2020 — the voltage rail and EEPROM communication spec are identical across the lineup.
• Bench tested on actual hardware: We ran this cell on a Legion 7i 15IMH chassis and monitored BMS handshake, charge acceptance, and ACPI reporting through a full charge cycle. The BMS completed cell recognition without error flags, and ACPI battery data populated correctly within the first charge session.
• First-cycle reset procedure: After fitting this cell, run the laptop unplugged until it reaches hibernate cutoff — do not interrupt. Then charge uninterrupted to 100%. This single discharge-charge cycle resets the BIOS battery learn cycle and clears the inaccurate health or capacity warning that appears after every cell swap on Legion hardware.

Why the Legion Y9000K shuts down at 20–30% after a battery swap

The Legion BIOS uses stored discharge curves from the old cell to predict when voltage will collapse. A new cell has a different curve, so the firmware misjudges the knee point and triggers a protective shutdown well above actual depletion. This is not a fault in the replacement cell — it is a calibration mismatch between fresh chemistry and stale BIOS data. Running two to three full discharge-to-hibernate, then charge-to-100% cycles forces the fuel gauge IC to rebuild its model against the new cell. After those cycles, the shutdown point drops back to the correct low-battery threshold — typically around 5% remaining.

BIOS reporting 0% capacity or "battery unknown" on first boot after install

The Legion BIOS reads EEPROM data embedded in the battery's BMS to populate health, Wh rating, and charge state. On a cold install, the BMS and BIOS have not yet completed their handshake, so the system reports 0% or flags the battery as unknown. Plug in AC power and leave the laptop on for at least 10 minutes without rebooting — this allows the ACPI battery driver to complete the initial EEPROM read. If the 0% reading persists after that window, remove AC, hold the power button for 15 seconds to clear the BIOS power state, then reconnect and boot.