About this replacement
Lenovo IdeaPad 120S-14IAP — 7.5V Li-Polymer Replacement Battery (0813007)
This 7.5V, 4050mAh (30.38Wh) Li-Polymer cell replaces the original battery in the Lenovo IdeaPad 120S-14IAP. It fits the 81A500GBGE, 81A50072GE, 81A500CCGE, 81A5006MGE variants and 18 additional sub-models in this line. OEM part numbers 5B10P23779 and BSNO3558E5 cross-reference to this same unit.
- IdeaPad 120S-14IAP compatibility: All listed sub-models share the same 7.5V battery rail, identical connector pinout, and BMS handshake protocol. Swapping between sub-models would cause no electrical conflict — the variance is cosmetic and regional, not electrical.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the IdeaPad 120S platform. The BMS communicated correctly with the EC firmware, accepted charge without tripping protection, and discharged cleanly to low-voltage cutoff without unexpected shutdowns.
- Post-install calibration tip: After fitting this cell, run the laptop down to hibernate cutoff on battery alone, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting poor battery health immediately after replacement
The IdeaPad 120S reads battery health from EEPROM data stored on the old cell. When a new cell goes in, the BIOS compares its charge history against a blank EEPROM and flags the result as degraded or unknown. This is a firmware artefact, not a fault with the new cell. Running one full discharge-to-hibernate followed by a full uninterrupted charge gives the BIOS enough data to recalibrate and clear the warning.
Laptop shuts down at 20–30% charge shown on the indicator
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The OS fuel gauge reports a percentage based on the old cell's discharge profile, so the displayed figure and the real remaining capacity fall out of sync. Under full CPU and display load, the cell voltage drops faster than the gauge predicts, and the system hits cutoff before the counter reaches zero. Two to three full discharge-and-charge cycles force the fuel gauge IC to relearn the curve and align the percentage readout with actual cell voltage.