Cars, trucks, RVs, and motorhomes run dual 12-volt batteries for various reasons. Depending on how you wire a two-battery 12-volt system, the result can be a 12-volt system or a 24-volt system—or even ...

An electrical relay is a type of heavy-duty, remote-control switch able to handle high-current accessories, yet capable of being actuated by substantially less current. Relays install between the ...