The Gadget’s a fuel or battery hog, and runs through its power reserves very quickly.
As a Minor Bad Trait, any roll of ‘Yes, But’ or ‘No, And’ results when using the Gadget means that the battery just ran out.
As a Major Bad Trait, the user needs to hook the Gadget up to a really big power source (like a power plant, or an alien ship’s power core) to get the thing working.