Re: Wiring sonar for my kayak; some questions
I don't have any knowledge of these two specific devices, but even though the input power is the same, the output may not be the same. Consider two 60 watt light bulbs. They each consume 60 watts, but they may put out differing ratios of heat vs light.
Its possible that the more expensive fishfinder uses a more efficient (but more expensive) technology to get better performance from the same input power. Or it could be that the marketing department decided they needed products at different price points and simply rewrote the published specs to make them look/seem different. Detroit automakers were masters at that game.
ultracrepidarian >> noting or pertaining to a person who criticizes, judges, or gives advice outside of his expertise