About this replacement
Acer Predator 15 G9-591 — 14.8V Li-ion Replacement Battery (AS15B3N)
This is a 14.8V, 5800mAh (85.84Wh) Li-ion battery for the Acer Predator 15 G9-591 series gaming laptop. It replaces OEM part numbers AS15B3N, KT.00803.004, and 4ICR19/66-2. The physical connector, cell count, and BMS handshake match the original G9-591 battery bay specification.
- G9-591 series fit: All G9-591 variants — including the 70F6, 713C, and 71DQ — share the same 4-cell 14.8V battery bay, connector pinout, and BMS communication protocol. One part number covers the full series.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS handshake validation on G9-591 hardware. The BMS negotiated correctly, protection circuits triggered at expected cutoff thresholds, and the BIOS recognised the pack without error codes.
- First-cycle calibration on the G9-591: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the false "poor health" warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor after replacement on the G9-591
The G9-591 BIOS reads health data from the battery's EEPROM on first contact. When a new cell arrives, the EEPROM charge history doesn't match what the BIOS expects from a worn-in pack, so it flags health as poor or unknown. This is a firmware interpretation issue, not a fault with the new cell. Running the full discharge-to-hibernate then uninterrupted charge cycle teaches the BIOS the actual capacity curve of the new cell and clears the warning within two to three cycles.
Predator 15 shutting down at 20–30% shown on the meter
Under full CPU and GPU load, the G9-591 draws enough current to cause a rapid voltage sag in a cell that hasn't been calibrated. The fuel gauge IC is still reading state-of-charge from the old cell's discharge curve, so the percentage shown doesn't match actual remaining capacity. When voltage drops below the BMS cutoff threshold, the laptop shuts off even though the OS still shows charge remaining. Complete two full discharge-to-100% cycles and the fuel gauge IC recalibrates against the new cell — shutdowns at false percentages stop after that point.