Asus Zenbook UX32LN Replacement Battery 11.3V 4400mAh

Asus Zenbook UX32LN / UX32LA — 11.3V Li-Polymer Replacement Battery (C31N1330)

This is an 11.3V, 4400mAh (49.72Wh) Li-Polymer battery for the Asus Zenbook UX32LN and UX32LA ultrabook series. It replaces OEM part numbers C31N1330 and 0B200-00070200. Physical dimensions are 294.68 × 85.06 × 10.30mm — measure your existing cell before ordering if you are unsure of your exact variant.

• UX32LN and UX32LA compatibility: Both models share the same three-cell Li-Polymer pack configuration, the same 11.3V nominal rail, and the same BMS handshake protocol through the EC controller. The connector pinout and physical form factor are identical across the UX32 range covered here.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a UX32LN unit. The BMS negotiated correctly with the embedded controller, current draw held steady under combined CPU and display load, and the protection circuit tripped at the expected low-voltage cutoff without a hard crash.
• Post-install calibration on UX32 series: After fitting this cell, run the laptop down to hibernate cutoff under normal use — do not force-drain it — then charge uninterrupted to 100% without using the machine. This gives the fuel gauge IC a full reference range to work from and clears the inaccurate health warning the BIOS logs after every cell swap.

BIOS reporting poor battery health immediately after fitting a new cell

The Asus EC stores the previous cell's charge history and wear data in EEPROM. When a new cell is installed, that stored data does not automatically reset — so the BIOS reads degraded cycle counts from the old record and flags health as poor or unknown. This is not a fault with the replacement cell. Running one full calibration cycle — full discharge to hibernate, then a complete uninterrupted charge to 100% — rewrites the learned parameters. After one or two cycles the BIOS health indicator will reflect the actual state of the new cell.

Laptop shuts down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The IC is still using reference points from the old, degraded cell, so it misjudges where the voltage cliff sits and triggers shutdown well before the cell is actually empty. It is not a faulty battery. Run two to three full discharge-to-hibernate and full charge cycles without interrupting the charge phase. After calibration, the gauge will track the new cell accurately and shutdowns at false low percentages will stop.