About this replacement
Lenovo G500 / G500S Series — 14.4V Li-ion Replacement Battery (L12S4E01)
This is a 14.4V, 2200mAh (31.68Wh) Li-ion replacement battery for the Lenovo IdeaPad G500 and G500S notebook series. It also fits the Z501 and S600 alongside 73 additional models sharing the same connector and voltage rail. Cross-referenced OEM part numbers include L12S4E01, L12M4E01, L12L4E01, and the L12S4A02 / L12M4A02 / L12L4A02 variants.
- G500 series compatibility: These models share a common 14.4V power rail, identical BMS handshake protocol, and the same locking slide connector. Swapping between G500 and G500S uses the same cell because Lenovo kept the battery architecture consistent across that production run.
- Bench tested on actual hardware: We ran this cell on a G500 unit and monitored the BMS through full charge and load cycles. The protection circuit responded correctly to charge termination and over-discharge cutoff without tripping false fault flags.
- BIOS learn cycle after install: After fitting this battery, run the laptop down to hibernate-cutoff on battery power alone, then charge uninterrupted to 100%. That single cycle resets the BIOS battery learn routine and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the G500 reports poor battery health immediately after a fresh cell install
The G500 stores battery state data in EEPROM on the original cell. When a new cell goes in, the BIOS reads stale cycle count and health metrics from its own firmware cache — not from the new cell directly. That mismatch triggers a poor health flag even though the cell is unused. Running one complete discharge-to-hibernate then a full uninterrupted charge clears the cached data and forces the BIOS to re-evaluate against the new cell's actual charge curve. Until that cycle runs, the health warning is a firmware artefact, not a cell fault.
Laptop shuts down at 20–30% remaining after battery swap
This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. Under combined CPU and display load, the G500 hits a voltage cliff earlier than the gauge predicts, and the system shuts down before the displayed percentage reaches zero. The fix is calibration: let the battery discharge fully to automatic hibernate, then charge straight to 100% without interruption. After two to three of these full cycles, the fuel gauge IC maps the new cell accurately and the early shutdowns stop. Target a resting voltage of approximately 16.8V at full charge to confirm the cell is topping out correctly.