About this replacement
Lenovo Yoga 9 14ITL5 Series — 15.52V Li-Polymer Replacement Battery (5B11D97138)
This 15.52V, 4700mAh (72.94Wh) lithium-polymer battery fits the Lenovo Yoga 9 14-inch 2-in-1 convertible line, including the 14ITL5 and 14IAP7 series. It replaces OEM part numbers 5B11D97138, L21B4PH0, L21C4PH0, L21D4PH0, and related variants. It slots into the same internal bay and uses the same connector as the original cell.
- Yoga 9 14ITL5 and 14IAP7 compatibility: Both series share the same 15.52V battery rail, connector pinout, and BMS handshake protocol. A single cell revision covers a wide span of regional SKUs including 82BG, 82LU, and 82BG008EPB variants without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a 14ITL5 unit. The BMS accepted the cell immediately, reported state-of-charge correctly, and thermal protection tripped at the expected threshold under sustained CPU and display load.
- Post-install learn cycle for the Yoga 9: After fitting this cell, 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 appears after every cell swap on this platform.
BIOS reporting battery health as poor immediately after replacement
The Yoga 9 BIOS reads health data from the cell's EEPROM, which stores charge history from the previous battery. A new cell has no logged cycles, so the BIOS flags it as degraded or unknown. This is not a fault with the replacement cell — it is a data mismatch. Run two full discharge-to-hibernate and full-charge cycles and the BIOS recalibrates against the new cell's actual capacity data.
Laptop shutting down between 15–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The IC maps percentage to voltage using data from the old cell, so the displayed percentage no longer matches actual charge state. Under full CPU and backlit display load, the cell voltage drops faster than predicted and the BMS triggers an emergency cutoff. Run two full calibration cycles — discharge fully to hibernate, then charge to 100% without interruption — and the gauge IC resets to the new cell's curve.