About this replacement
Lenovo IdeaPad 5-15ARE05 / 5-15IIL05 / 5-15ITL05 — 15.36V Li-Polymer Replacement Battery (L21C4PH2)
This is a 15.36V, 4750mAh (72.96Wh) Li-Polymer battery for the Lenovo IdeaPad 5 15-inch notebook series. It fits the IdeaPad 5-15ARE05, 5-15IIL05, and 5-15ITL05 models. It replaces OEM part numbers L21C4PH2, L21D4PH2, L21L4PH2, L21M4PH2, SB11B53887, and SB11F48157.
- IdeaPad 5 15-inch series compatibility: The ARE05, IIL05, and ITL05 share the same battery bay geometry, connector pinout, and BMS handshake protocol. All three models draw from the same 15.36V four-cell Li-Polymer platform, so one cell fits all three without modification.
- Bench tested on actual hardware: We cycled this cell on an IdeaPad 5-15ITL05 under mixed CPU and display load. The BMS held charge correctly across full discharge cycles, and BIOS reported capacity within normal bounds after calibration.
- Post-install calibration on IdeaPad 5: After fitting, run the laptop on battery until it hibernates at low voltage, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this series.
BIOS reporting poor battery health immediately after replacement
The IdeaPad 5 BIOS stores battery health data in EEPROM tied to the original cell. When a new cell is installed, the BIOS compares live readings against stale EEPROM values and flags poor health — even when the new cell is fine. This is not a fault with the replacement. Running one complete discharge-to-hibernate cycle followed by a full uninterrupted charge gives the BIOS enough data to overwrite the old EEPROM values. After two to three full cycles, the health warning clears and capacity reporting stabilises.
Laptop shuts down at 20–30% battery shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The gauge reports 20–25% remaining, but the cell voltage has already dropped below the BMS cutoff threshold under full CPU and display load — so the system shuts down. It is not a faulty cell. Run two full discharge-to-hibernate cycles without interruption, letting the fuel gauge IC map the new cell's voltage-to-capacity relationship. After calibration, the gauge tracks accurately and the early shutdown stops.