Systemax N243 14.8V Replacement Battery 23-U74201-31

Systemax N243 / N244 Series — 14.8V Li-ion Replacement Battery (23-U74201-31)

This is a 14.8V, 4400mAh Li-ion replacement battery for the Systemax N243 and N244 series notebooks. It replaces OEM part numbers including 23-U74201-31, UN243, and BAT-243S1. Capacity is 65.12Wh — matching the original cell specification.

• N243 and N244 series compatibility: Both series share the same battery bay geometry, connector pinout, and BMS handshake protocol. The same 4-cell Li-ion pack at 14.8V nominal powers both platforms without modification.
• Bench tested on actual hardware: We ran the cell through charge and discharge cycles on compatible hardware. The BMS negotiated correctly, charge termination triggered at full capacity, and the protection circuit responded normally to load spikes during CPU stress testing.
• First-cycle reset after installation: After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. 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.

BIOS reporting battery health as poor immediately after replacement

The BIOS stores charge history and health data from the old cell in its firmware registers. When a new cell is installed, those registers still reflect the degraded state of the previous battery. The system reads that cached data and flags poor health — not the new cell's actual condition. Running one complete discharge-to-hibernate followed by a full uninterrupted charge clears the learned data and forces the BIOS to recalibrate against the new cell's actual capacity.

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

This is a fuel gauge calibration fault, not a hardware failure. The fuel gauge IC is still referencing discharge curves from the old, degraded cell and predicts voltage collapse too early. Under full CPU and display load, it triggers a shutdown before the gauge reaches zero because its model no longer matches the new cell's actual discharge profile. Complete two to three full discharge-to-hibernate and uninterrupted-charge cycles — after that the IC recalibrates and the gauge will track accurately down to the real cutoff voltage of 11.1V.