1500W? At 12V that's 125A - That is fucking dangerous! Most sockets are rated at 20A. Most inverters that are >300W use crocodile clips, or preferably screw-down terminal rings. The cable looks way too thin too. That's a fire waiting to happen....
no kidding. Even 35A is enough to melt a 12v plug spring into the plastic surround.... don't ask me how i know....