When I got my Elite 5DSI (used) it happened to come with two power/tdx cords in the deal ... I just hooked one up on the boat & used the other off a jumper battery inside my home.

Now that I have the Hook 7 (E5DSI replacement) and only one power cord ... I hook it up to one of the boat batteries that are kept on charge inside my home. It hasn't been hooked up/mounted on the boat yet. When it is finally mounted on the boat ... I won't be able to do any "playing around" with it in the comfort of my living room, any longer, unless I purchase another power cord. The Hook 7 has separate power cord & transducer cord.