Each Dell laptop uses an AC adapter that is of different wattage. This can depend on the hardware configuration of the laptop. Dell laptops come with a 45 W, 65 W, 90 W, 130 W, 180 W, or 240 W AC adapter. For optimal performance, Dell Technologies recommends using the original AC adapter that came with the Dell laptop. The AC adapter's wattage information is printed on a label on the bottom of the AC adapter. Verify the AC adapter type in the BIOS options. The AC adapter information is most often found on the main screen of the BIOS. The laptop may show an error message such as "The AC adapter type cannot be determined.This prevents optimal computer performance" or "Unknown or incorrect AC adapter detected." If the AC adapter type is None - Verify that the AC adapter is connected to the laptop, the LED on the AC adapter is ON, and the correct AC adapter is connected to the laptop.