About this replacement
Lenovo IdeaPad 5-15IIL05 — 11.52V Li-Polymer Replacement Battery (L19M3PF6)
This is an 11.52V, 4950mAh (57.02Wh) Li-Polymer battery for the Lenovo IdeaPad 5-15IIL05 15-inch notebook. It replaces OEM part numbers L19M3PF6, 5B10W86944, and SB10W86952. It fits the 81YK003VMZ, 81YK0038MX, and 81YK variant codes in that line.
- IdeaPad 5-15IIL05 variant coverage: The 81YK suffix variants — 003VMZ, 0038MX, and the base 81YK — all share the same battery bay dimensions, the same 3-cell Li-Polymer configuration, and the same BMS communication protocol over the SMBus line. One battery fits every model in that suffix group.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on an IdeaPad 5-15IIL05 chassis. The BMS handshake initialised correctly, charge termination triggered at 100% without fault codes, and the protection circuit responded normally to over-discharge conditions.
- Post-install discharge cycle: After fitting this battery, run the laptop down to hibernate cutoff on a real workload — do not let it sleep, let it hibernate. Then charge it uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after any cell swap on this platform.
BIOS reporting poor battery health immediately after fitting a new cell
The IdeaPad 5 BIOS reads health data from the battery EEPROM and compares it against the previous cell's stored cycle count and capacity records. A brand-new cell has a blank or factory-default EEPROM state, which the BIOS misreads as a degraded or unknown battery. This is a firmware calibration issue, not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% resets the learn cycle and updates the BIOS health register correctly.
Laptop shuts down abruptly while the gauge still shows 20–30%
This happens when the fuel gauge IC's discharge curve is still mapped to the old cell's chemistry profile. Under full CPU and display load, the new cell's actual voltage drops faster than the IC predicts, and the system hits the hardware low-voltage cutoff before the percentage gauge reaches zero. The gauge is reading a model, not the real cell. Two to three full discharge-and-charge cycles recalibrate the fuel gauge IC against the new cell's actual discharge curve. After calibration, shutdowns at 20–30% stop and the gauge tracks to within a few percent of true remaining capacity.