It's too bad you guys are so in love with your high power locaters. My Eagle Cuda 242 ran for 2 trips of 11 days last year and made it half way through our 14 day trip this year before I had to change batteries - 8 lithium AA. From a canoe these cheap locaters priced under $100 do all that's needed to find depth, bottom structure and fish on a canoe trip. The newest basic Lowrance X4 has similar power consumption to the Eagle Cuda series so I would expect similar battery life. I am a bit conservative with my locater usage and only use it when fishing and even then I sometimes turn it off while trout fishing in deep deep water. At the weight of 8 lithium AA's and the weight of the display unit itself it would take alot more convincing to get me to "upgrade". My entire locater, transducer, wiring, suction cup and 2 sets of batteries weighs 18 ounces. And the total investment is still under $100.
For those new to depth finders don't think that this is more complicated than it really needs to be.
One more observation, my locater functioned fine until the voltage dropped below 8 volts and then the display faded out. That was with lithium batteries. When I've used alkaline batteries the first sign of failure came at about 9 volts when the unit was unable to find the bottom in deep water (over 50 feet) and they would last about 1/2 of a typical trip. I easily am seeing 4-5 times more battery life with lithiums and I like the operating characteristics of lithium batteries better too.