I use my Hummingbird 798 ci si unit on a utility box with battery and ice ducer and it works really good. I turn off the down and side imaging screens and use it with flasher mode or regular fishfinder mode depending on species. For Lakers the fishfinder mode is nice to see the history of what just happened like the streaks up and down... It also has GPS with navionics mapping which is helpful for finding and marking spots.
Since you bought the Lowrance Elite 4 you could buy the Lowrance Ice Pack PPP 18 for about $150 which comes with the carrying bag, ice transducer, battery, charger and a few tackle boxes that fit into the bag. It's really nice.