I've been re-reading this whole thread and was reminded that Quentin is the one that uses that Ryobi 18 v Lithium battery set-up.

Maybe if he reads this he could go into greater detail (maybe pics) on exactly how his set-up is wired and how he's set-up his fish finder?

I'm looking at my Ryobi battery manual. It talks about battery protection features designed in to the battery packs to protect battery cells and maximize battery life.

For my weed trimmer, it says if the trimmer stops during use, release the trigger to reset and resume operation. If the tool still doesn't work, the battery needs to be re-charged.

I wonder Red Owl if you would of "re-set" the battery by turning the fish finder on-off, if that would of made a difference?