Eurocom Sky MX5 R3 Replacement Battery 14.8V 4000mAh

Eurocom Sky MX5 R3 — 14.8V Li-ion Replacement Battery

This is a 14.8V, 4000mAh (59.2Wh) Li-ion replacement battery for the Eurocom Sky MX5 R3 laptop. It fits the Sky MX5 R3 portable workstation and restores battery-powered operation when the original cell has degraded or failed. Voltage and connector match the OEM spec for this chassis.

• Sky MX5 R3 platform fitment: The Sky MX5 R3 uses a 14.8V four-cell Li-ion pack with a specific BMS handshake tied to this voltage rail. Swapping in a cell at a different voltage would prevent the charge controller from initiating — this replacement matches that rail exactly.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Sky MX5 R3 chassis. The BMS handshake initialised on first connection, the charge controller stepped through its CC/CV stages without interruption, and the cell reached rated voltage at termination.
• First-cycle calibration on the Sky MX5 R3: After installing, run one full discharge until the laptop hibernates at cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle on the Sky MX5 R3 and clears the inaccurate health warning that appears after every cell swap.

Why the Sky MX5 R3 BIOS flags a new battery as poor health

The Sky MX5 R3 BIOS stores battery health data in EEPROM tied to the original cell's cycle count and rated Wh. When a new cell is installed, that stored data no longer matches the cell reporting to the system, so the BIOS flags health as degraded or unknown. This is a data mismatch — not a fault with the replacement cell. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the BIOS learn cycle and overwrites the stale EEPROM values. After one or two full cycles, the health indicator should update to reflect the new cell accurately.

Sky MX5 R3 shutting down at 20–30% charge shown

This happens when the fuel gauge IC hasn't calibrated against the new cell's actual discharge curve. Under full CPU and display load, the Sky MX5 R3 draws enough current to expose a voltage cliff the uncalibrated gauge doesn't anticipate — the system shuts down for protection before the displayed percentage reaches zero. The fix is completing two or three full discharge-to-hibernate, then charge-to-100% cycles without interruption. After calibration, the fuel gauge maps the new cell's curve correctly and the early shutdowns stop.