Unusual battery cell failures leading to sudden power loss without warning

An instant shutdown at 30–50% charge usually points more toward the battery pack, its controller, or firmware than a Windows power-plan setting. First, run Command Prompt as administrator and create a report with powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html". Compare Design Capacity with Full Charge Capacity and review Recent Usage for abrupt percentage drops.

Then test twice: once on AC power with the battery connected, and once on battery after a full charge. If it is stable on AC but dies at a repeatable percentage on battery, the pack is the leading suspect. Install the laptop manufacturer's current BIOS, chipset, and battery/ACPI updates, then run its built-in hardware diagnostics.

Event Viewer may show Kernel-Power 41 after the shutdown, but that only confirms an unclean power loss. If the battery is swollen, unusually hot, or the laptop is under warranty, stop using it and arrange manufacturer service rather than repeatedly recalibrating it.