Lots of folks are using the Garmin striker 4plus. It’s got DI and GPS for $180. They hook them to the little rechargeable 12v sealed batteries.
Ive got a striker4 ill sell cheap if you want to try it. It is not the di. It was $109.00 new. Ill sell it for $40.00/ you pay shipping or come get it. The transducer will not go in a scupper hole. You will need a transducer mount, wouldnt be hard at all to make one. Works fine, upgraded a while back.