Lenovo Xiaoxin Air Pro Compatible Battery 15.2V 3550mAh 5B10M55950

Lenovo Xiaoxin Air Pro / IdeaPad 720S-14IKB — 15.2V Li-Polymer Replacement Battery (5B10M55950)

This 15.2V, 3550mAh (53.96Wh) Li-Polymer battery replaces the original cell in the Lenovo Xiaoxin Air Pro and the IdeaPad 720S-14IKB family, including part numbers L16C4PB2, L16L4PB2, and L16M4PB2. It fits a slim 288.60 × 127.00 × 5.75mm footprint and connects directly to the IdeaPad 720S board without modification. If the original cell has degraded, swollen, or dropped below usable capacity, this unit restores the laptop to portable operation.

• IdeaPad 720S-14IKB compatibility: The 720S-14IKB variants — including 81BD003HGE, 80XC0004US, and 81BD003YMH — all share the same 15.2V four-cell Li-Polymer rail, identical connector pinout, and the same BMS handshake protocol. One SKU covers the full run of these boards.
• Bench tested on actual hardware: We ran this cell on a 720S-14IKB board and confirmed the BMS accepted the EEPROM handshake, charge current ramped correctly through CC and CV phases, and the board did not flag a protection fault at any state of charge.
• First-cycle calibration on the 720S-14IKB: After installing, run one full discharge to hibernate cutoff — do not force shutdown — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that consistently appears after a cell swap on this platform.

BIOS reporting battery health as poor immediately after replacement

The IdeaPad 720S-14IKB reads health data from the battery's EEPROM and compares it against the charge history stored in firmware. A new cell has no accumulated cycle data, so the BIOS interprets the mismatch as degradation — it will display "Poor" or "Replace soon" even when the cell is brand new. This is a firmware read issue, not a fault with the replacement unit. Running one complete discharge-to-hibernate then a full uninterrupted charge gives the BIOS enough data to recalculate health correctly. After two to three cycles the health indicator updates to an accurate value.

Laptop shutting down at 20–30% shown on the fuel gauge

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The gauge was trained on the old, degraded cell and still maps the old voltage thresholds to charge percentages — so what it reads as 25% is actually at or below the BMS low-voltage cutoff for the new cell. The laptop shuts down because the cell voltage has already hit the protection floor, not because Windows miscounted. Run two full discharge-to-hibernate and full charge cycles without interruption. After those passes, the fuel gauge IC resets its curve and the percentage readings stabilise to match the actual cell state.