SeaRay ... I have an extra set of power/tdx cables for my Lowrance Elite 5DSI and run it in my home by using a portable jumper battery that I bought at Wally World a few years ago for around $30. I think this is the current version of that model unit : Amazon.com: Schumacher XP400 400 Peak Amp Instant Portable Power Source: Automotive

I don't know if I would expect it to jumpstart my truck battery, but for "playing" with my DSI unit .... it has worked out fine.

... cp