Our diesel portable fire pump has no permanent connection to the power grid and the batteries don't hold a charge in winter. Therefore, it is easier to connect the cables to the car battery, which is charged for operation. The old terminals were small and difficult to use, leading to broken wires and overheating. They are ideal for all needs, they are large enough to be mounted on the terminal and withstand the stress. However, it's small enough to be hidden away in a moisture-proof box on a trailer.