About this replacement
Lenovo Legion S7 16IAH7 / 16ARHA7 — 15.52V Li-Polymer Replacement Battery (5B11F29413)
This is a 15.52V, 6250mAh (97Wh) Li-Polymer replacement battery for the Lenovo Legion S7 16-inch gaming laptop series. It fits the Legion S7 16IAH7 and 16ARHA7 across a wide range of regional SKUs, including 82TF008SRK, 82TF001XMJ, 82TF002GPH, and 82UG0011TW. It replaces OEM part numbers 5B11F29413, 5B11F29420, L21B4PE1, L21C4PE1, and L21M4PE1.
- Legion S7 16IAH7 and 16ARHA7 compatibility: Both the Intel (IAH7) and AMD (ARHA7) variants of the S7 16 share the same 15.52V four-cell battery architecture and connector pinout. The BMS handshake and cell voltage rails are identical across these platforms, which is why one replacement covers both processor generations.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Legion S7 16IAH7 unit. The BMS balanced all four cells without error, held the 15.52V nominal rail under sustained CPU and GPU load, and passed the BIOS battery detection handshake on first connection.
- Post-install calibration cycle: After fitting this battery, run it down until the laptop hibernates at the BIOS cutoff voltage, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after a cell swap.
Legion S7 shutting down at 20–30% shown after battery swap
The Legion S7 draws hard on the battery when the CPU and discrete GPU both spike simultaneously — common during game loading or benchmark runs. A new cell's fuel gauge IC hasn't mapped the actual charge curve yet, so the reported percentage lags behind real state of charge. When the cell voltage drops below the BMS protection threshold, the laptop cuts out even though the OS shows remaining charge. Run two or three full discharge-to-hibernate and full-charge cycles — the fuel gauge IC recalibrates against the new cell and the premature shutdowns stop. After calibration, the BIOS-reported cut-off should align at or below 10% on screen.
BIOS reporting battery health as "poor" or "consider replacing" immediately after install
This warning reads from EEPROM data written by the outgoing cell — cycle count, health percentage, and charge history carried over from the old battery. The new cell hasn't yet written its own EEPROM baseline to the system. Run the Lenovo Vantage battery gauge reset function, or perform one full discharge-to-hibernate followed by a complete uninterrupted charge. After that cycle completes, restart into the BIOS and check the battery status page — the health flag should clear and report normal.