About this replacement
Acer Aspire V5-171 / Aspire One 725 / 756 — 14.4V Li-ion Replacement Battery (AL12B32)
This is a 14.4V, 2200mAh (31.68Wh) Li-ion replacement battery for the Acer Aspire V5-171, Aspire One 725, Aspire One 756, and Chromebook AC710. It replaces OEM part numbers AL12B32, AL12B72, KT.00407.002, KT.00403.004, AL12B31, and AL12X32. The connector pinout and BMS handshake match original Acer specifications for these models.
- Aspire V5-171 and Aspire One platform fit: These models share the same 14.4V four-cell Li-ion rail, connector housing, and BMS communication protocol — which is why a single cell replaces across both the V5 ultrabook and the One 725/756 subnotebook lines.
- Bench tested on actual hardware: We ran this cell on an Aspire V5-171 and an Aspire One 756. The BMS handshake completed on first insertion, BIOS recognised the battery without error codes, and charge acceptance was normal from first cycle.
- BIOS learn cycle after installation: After fitting this battery, run the laptop down to hibernate cutoff on battery only — no charger connected — then charge uninterrupted to 100%. This forces the BIOS to re-learn the new cell's actual capacity and clears the inaccurate health warning that appears after every cell swap on Acer firmware.
BIOS reporting poor battery health immediately after fitting a new cell
Acer's BIOS stores battery health data in an EEPROM register tied to the old cell's charge history. When a new cell goes in, the BIOS reads stale EEPROM values and flags the battery as degraded — even though the cell is new. This is a firmware calibration issue, not a fault with the replacement. One full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the register. After that cycle, BIOS health status returns to normal.
Aspire V5-171 shutting down at 20–30% charge remaining
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual voltage curve. At moderate CPU and display load, the IC misreads the remaining capacity and triggers a shutdown before the cell is genuinely empty. It is not a defective cell. Run two to three full discharge-to-hibernate cycles and the fuel gauge IC recalibrates — shutdowns shift to the correct low-voltage cutoff near 3.0V per cell.