Lenovo IdeaPad 720S-15IKB Compatible Battery 15.3V 5050mAh

Lenovo IdeaPad 720S-15IKB / V730-15 — 15.3V Li-Polymer Replacement Battery (L17C4PB1)

This is a 15.3V, 5050mAh (77.27Wh) lithium-polymer replacement battery for the Lenovo IdeaPad 720S-15IKB (81AC) and V730-15 series laptops. It replaces OEM part numbers L17C4PB1, L17M4PB1, 5B10P35082, 5B10P35083, and 5B10P35084. The cell matches the original voltage rail and connector pinout for these 15-inch ultrabook platforms.

• IdeaPad 720S-15IKB and V730-15 platform fit: Both the IdeaPad 720S-15IKB (81AC) and V730-15 variants share the same four-cell Li-Polymer architecture, 15.3V nominal rail, and BMS communication protocol — which is why a single part number covers all listed models. The connector and BMS handshake are identical across the 81AC and V730-15-ISE subvariants.
• Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS communication checks on the IdeaPad 720S-15 platform. The BMS initialised correctly, BIOS recognised the battery without flagging an unknown device, and charge current stepped down as expected through each phase.
• Post-install calibration cycle: After fitting this cell, run the laptop down fully until it hibernates on its own, then charge it uninterrupted to 100% without unplugging mid-cycle. This resets the BIOS battery learn cycle and clears the inaccurate health warning that typically appears after a cell swap on Lenovo ultrabooks.

BIOS reporting battery health as poor immediately after replacement

Lenovo's BIOS reads health data from the battery's EEPROM, which stores cycle count and capacity history from the old cell. A brand-new cell has no matching history, so the BIOS flags it as degraded — this is a firmware read issue, not a fault with the new battery. Running one full discharge-to-hibernate followed by a complete uninterrupted charge gives the fuel gauge IC enough data to recalibrate against the new cell's actual capacity. After two to three full cycles, the health reading in Lenovo Vantage or the BIOS battery report normalises.

Laptop shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated to the new cell's voltage curve. The displayed percentage is based on the old cell's discharge profile, so when voltage drops sharply under combined CPU and display load — typically around 14.8V — the system cuts out before the gauge reaches zero. The fix is a calibration cycle: let the laptop discharge fully to hibernate, then charge to 100% without interruption. After two full cycles, the gauge tracks the new cell accurately and the premature shutdowns stop.