Dell Alienware 17 Replacement Battery 14.8V 5600mAh 2F8K3

Dell Alienware 17 / M17X R5 / M18X R3 — 14.8V Li-ion Replacement Battery (2F8K3)

This 14.8V, 5600mAh (82.88Wh) lithium-ion battery replaces the original Dell part 2F8K3 in the Alienware 17, Alienware 18, Alienware M17X R5, and Alienware M18X R3. It uses the same OEM connector, voltage rail, and BMS handshake protocol as the factory cell. Physically it measures 175.76 × 86.48 × 19.76mm — match this against your bay before installing.

• Alienware 17 / 18 / M17X R5 / M18X R3 platform compatibility: These models share the same 14.8V four-cell architecture, identical connector pinout, and a common BMS communication protocol over the SMBus line — which is why one cell fits across the range without firmware modification.
• Bench tested on actual hardware: We ran this cell on an Alienware 17 chassis under a full CPU plus discrete GPU load cycle. The BMS completed charge handshake correctly, cell balancing activated at 16.4V pack voltage, and the protection circuit tripped at the correct undervoltage threshold without nuisance cutoffs.
• Post-install calibration on Alienware systems: After fitting this cell, run the laptop down to automatic hibernate cutoff — do not force shutdown — then charge uninterrupted to 100%. This triggers the BIOS battery learn cycle, resets the fuel gauge IC against the new cell's actual capacity, and clears the "battery health poor" flag that appears after every cell swap on Alienware firmware.

BIOS reporting battery health as poor immediately after replacement

The Alienware BIOS reads health data from EEPROM registers in the old cell and caches it. When a new cell is installed, the BIOS compares the new cell's reported charge history against that cached data and flags a mismatch as degraded health. This is a firmware artefact — not a fault with the replacement cell. Running one full discharge-to-hibernate then a complete uninterrupted charge cycle forces the BIOS to re-initialise its battery learn table against the new cell. After two to three full cycles, the health indicator returns to normal.

Laptop shutting down abruptly at 20–30% charge shown

This symptom on Alienware 17 occurs when the fuel gauge IC has not yet calibrated to the new cell's actual discharge curve. The gauge underestimates remaining capacity, and when Alienware's aggressive power management detects a projected voltage cliff under GPU plus CPU combined load, it forces an immediate shutdown to protect the pack. It is not a defective cell — the gauge needs two or three full discharge-to-hibernate cycles to map the new cell accurately. After calibration, the shutdown threshold tracks correctly and the 20–30% premature cutoff stops. If the fault persists beyond three cycles, check that BIOS is current and battery settings in Dell Command Power Manager are not overriding the learn cycle at 16.8V pack floor.