Hasee U45A2 Replacement Battery 11.4V 4100mAh

Hasee U45A2 / Kingbook U43S1 Series — 11.4V Li-Polymer Replacement Battery (PF4WN-00-13-3S1P-0)

This is an 11.4V, 4100mAh (46.74Wh) lithium-polymer replacement battery for the Hasee U45A2 and related slim notebooks. It fits the Kingbook U43S1, U47S2, Kingbook U47T1, and several additional models sharing the same 3S1P cell configuration. The OEM part numbers PF4WN-00-13-3S1P-0, PF4WN-00-17-3S1P-0, PF4WN-03-17-3S1P-0, and U45A1HPFS01 all cross to this cell.

• U45A2 and Kingbook platform fit: These models share a common 3S1P lithium-polymer pack format — same voltage rail, same connector pinout, and the same BMS handshake protocol. Swapping between any of these models uses the same physical and electrical spec.
• Bench tested on actual hardware: We cycled this cell through charge, full load discharge, and BMS trip conditions on U45A2 hardware. The protection circuit triggered correctly at low-voltage cutoff and the charge controller accepted a full charge cycle without fault codes.
• Post-install calibration on the U45A2: After fitting, run the laptop on battery until it hibernates on low charge, then plug in and charge uninterrupted to 100% without using the machine. This forces the BIOS battery learn cycle to reset against the new cell 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 Hasee U45A2 BIOS reads health data from the battery's EEPROM on first detection. When a new cell arrives, that EEPROM data does not match the charge history the BIOS expects, so it flags health as poor or unknown — even on a brand new pack. This is a firmware read mismatch, not a fault with the replacement cell. Running one full discharge-to-hibernate and uninterrupted charge-to-100% cycle resets the learn cycle. After that single calibration pass, the BIOS health indicator updates correctly.

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

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual charge curve. The old calibration data still in memory predicts voltage behaviour based on the worn cell it replaced — so it misreads the new cell's voltage cliff and triggers shutdown early. It is not a battery fault. Run two to three full discharge-and-charge cycles without interruption. By the third cycle the fuel gauge IC recalibrates and the shutdown point drops back to below 5% as normal.