Fujitsu Amilo EL6800 Compatible Battery 14.8V 4400mAh

Fujitsu Amilo EL6800 Series — 14.8V Li-ion Replacement Battery (UN243S9-P)

This is a 14.8V, 4400mAh (65.12Wh) lithium-ion battery for the Fujitsu Amilo EL6800 and EL6810 notebooks. It replaces OEM part numbers UN243S9-P and UN243S. The connector and BMS handshake match the original Fujitsu cell, so the battery seats and communicates correctly with the system board.

• EL6800 and EL6810 compatibility: Both models share the same 14.8V power rail, battery bay dimensions, and BMS communication protocol. A single cell covers both because the system board uses identical charge-controller firmware across the EL6800 and EL6810 SKUs.
• Bench tested on actual hardware: We ran the cell through a full charge-discharge cycle on an EL6800 unit. The BMS accepted the cell without a firmware rejection event and the charge controller reached 100% without throttling. Cell voltage held stable across the discharge curve.
• Post-install discharge cycle on the Amilo EL6800: After fitting this cell, run one full discharge to the hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on the Amilo platform.

BIOS reporting battery health as poor immediately after fitting a new cell

The Amilo EL6800 BIOS reads health data stored in the battery's EEPROM and compares it against the old cell's logged cycle count and capacity history. A new cell has no matching history, so the BIOS flags it as degraded on first boot. This is a data-mismatch warning, not a hardware fault. Run one full discharge-to-hibernate followed by a full uninterrupted charge to let the system write a fresh baseline to the EEPROM. After one or two cycles the health indicator updates correctly.

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

This happens when the fuel gauge IC has not yet calibrated its discharge curve against the new cell's actual chemistry. The IC was tuned to the old cell's degraded voltage curve, so it misreads the new cell's voltage floor and triggers a low-battery shutdown too early. The fix is to complete two or three full discharge-to-hibernate and full-recharge cycles without interruption. By the third cycle the fuel gauge IC recalibrates and the shutdown threshold aligns with the actual remaining capacity — typically shifting the real cutoff below 10%.