About this replacement
Lenovo ThinkPad E480S / E490S — 11.25V Li-Polymer Replacement Battery (L18M3P52)
This is an 11.25V, 3650mAh (41.06Wh) Li-Polymer battery for the Lenovo ThinkPad E480S and E490S. It replaces OEM part numbers L18M3P52, L18M3P51, L18C3P51, 02DL001, 02DL000, 02DL002, SB10K97640, SB10K97639, and SB10K97641. If your original cell is no longer holding a charge or BIOS is flagging poor battery health, this cell fits directly into those chassis.
- E480S and E490S platform fit: Both models share the same battery bay geometry, connector pinout, and BMS handshake protocol — Lenovo used a common battery spec across the S-suffix E4x0 series, which is why this cell carries cross-compatible OEM part numbers for both.
- Bench tested on actual hardware: We ran this cell in a ThinkPad E480S and confirmed the BMS negotiated correctly — BIOS recognised the battery, voltage reporting stabilised within one charge cycle, and charge current ramped normally from trickle to full rate without a fault flag.
- First-cycle calibration on ThinkPad E-series: After fitting this cell, run a full discharge down to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the status page immediately after a cell swap.
BIOS reporting poor battery health after fitting a new cell
ThinkPad firmware reads health data from the battery's EEPROM and compares it against a stored baseline from the old cell. A freshly swapped cell has no charge history logged, so BIOS flags it as degraded or unknown — even when the cell is brand new. This is a firmware interpretation issue, not a hardware fault. Running one full discharge-to-hibernate then a complete uninterrupted charge gives BIOS enough cycle data to reset the health reading to normal.
Laptop shuts down at 20–30% charge shown on screen
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual voltage curve. The gauge loses accuracy when a new cell is installed, so it under-reads remaining capacity — the system hits a low-voltage shutdown before the displayed percentage reaches zero. Under full CPU plus display load, voltage sag accelerates this cutoff point. Complete two full discharge and charge cycles to let the fuel gauge IC re-map the new cell's curve, and the reported percentage at shutdown will drop back toward single digits.