About this replacement
Lenovo Legion S7 15IMH5 — 15.36V Li-Polymer Replacement Battery (L19C4PC3)
This is a 15.36V, 4500mAh (69.12Wh) Li-Polymer replacement battery for the Lenovo Legion S7 series gaming laptop. It fits the Legion S7 15IMH5 (82BC), Legion R9000X, and several closely related variants. When the original cell degrades and the laptop stops holding a charge off AC power, this cell restores portable operation.
- Legion S7 / R9000X platform fit: These models share the same 15.36V four-cell architecture, connector pinout, and BMS handshake protocol. OEM part numbers L19C4PC3, L19M4PC3, SB10Z49582, and 5B10Z49581 are all cross-compatible within this platform — the difference is supplier sourcing, not specification.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS communication checks on a Legion S7 15IMH5 unit. The BMS recognised the cell immediately, reported correct voltage, and the fuel gauge IC began tracking state-of-charge without errors after two full cycles.
- BIOS learn cycle after installation: 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 after every cell swap on Lenovo systems.
BIOS reporting battery health as "Poor" after fitting a new cell
Lenovo's BIOS reads health data from the cell's EEPROM, which stores cycle count and wear metrics from the previous battery. When a new cell is installed, that EEPROM data resets, and the BIOS briefly misreads the initialisation state as degraded. This is a firmware calibration lag, not a fault with the replacement cell. Running one full discharge-to-hibernate then a full uninterrupted charge forces the BIOS learn cycle to complete. After that cycle, health status updates to normal and the warning clears.
Laptop shutting down at 20–30% displayed charge under gaming load
Under full CPU and GPU load, the Legion S7 draws significantly more current than during light use. If the fuel gauge IC hasn't completed calibration cycles against the new cell, it maps the old cell's voltage curve onto the new one. The result is that the displayed percentage doesn't match the real state-of-charge — the cell hits its voltage cliff before the OS expects it, triggering an abrupt shutdown. Complete two full discharge-to-hibernate cycles under normal load to allow the fuel gauge IC to re-map the curve accurately. After calibration, the reported cutoff aligns with the actual cell voltage floor at 12.0V.