About this replacement
Lenovo IdeaPad 720s — 7.68V Li-Polymer Replacement Battery (L16C4PB3)
This 7.68V, 6200mAh Li-Polymer cell replaces the original battery in the Lenovo IdeaPad 720s thin-and-light laptop. It fits the 720S-13IKB, 720S-13ARR, and related 13-inch variants. OEM part numbers L16C4PB3, L16L4PB3, and L16M4PB3 are all covered by this unit.
- 720s compatibility across revisions: The 13IKB and 13ARR share the same flat Li-Polymer pack form factor, connector pinout, and BMS handshake protocol — same voltage rail at 7.68V, same physical envelope at 278.22 x 95.50 x 4.26mm. One cell fits both Intel and AMD board revisions.
- Bench tested on actual hardware: We cycled this cell through charge, idle draw, and sustained CPU load on a 720S-13IKB. The BMS held charge termination correctly at full capacity and did not trip during the load transitions.
- Post-swap calibration on the 720s: After fitting this cell, run one full discharge to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor after replacement on the 720s
The 720s BIOS reads health data from EEPROM registers written by the original factory cell. A new cell ships with fresh EEPROM values that don't match the aged baseline the firmware expects. This triggers a false "poor health" or "replace battery" flag immediately after installation. Running one full discharge-to-hibernate followed by a full uninterrupted charge gives the BIOS enough cycle data to recalibrate and clear the warning.
720s shutting down at 20–30% charge shown on screen
This is a fuel gauge IC calibration issue, not a faulty cell. The gauge IC was calibrated against the old degraded cell and its voltage-to-capacity curve no longer maps accurately to the new chemistry. Under full CPU plus display load, voltage drops faster than the stale curve predicts, and the system hits its hardware cutoff before the displayed percentage reaches zero. Two to three full discharge-and-charge cycles will re-teach the IC. After the third cycle, the gauge should track the actual cell voltage and report accurately down to the real cutoff near 6.0V.