I am looking at adding a fishfinder to my kayak, but want to keep the weight down as much as possible. I like what I read about the RayMarine Dragonfly4. I am cautious though not knowing what I would need for a battery. I do not want to pack a large 12 volt battery. I have looked into the Hawkeye Fishtrax 1C, but the only reviews seem to be by the manufacturer. I am also still in the dark after researching them as to whether they show structure or not. My primary use will be for finding structure, depth and bottom contours. Anyone have experience with small portable fishfinders?